Manufacturing method of integrated busbar and integrated busbar

Abstract

The invention provides a manufacturing method of an integrated busbar and the integrated busbar. According to the manufacturing method and the integrated busbar, the blind groove is formed in the circuit board, the light penetrates through the blind groove and irradiates the solder paste arranged corresponding to the blind groove, the solder paste is melted, and therefore the circuit board is connected with the flexible flat cable, and the process is simple. In addition, at the connection interface between the solder paste and the copper bar wire of the flexible flat cable, copper and tin form a firm intermetallic compound IMC (the main component is Cu6Sn5), the bonding strength is high, and the reliability of the integrated busbar can be improved. Besides, illumination only locally acts on the light absorption layer, other places are not heated, the adhesive film layer of the flexible flat cable can be made of low-temperature-resistant PET with the cost advantage, and the adhesive film layer deviating from the welding position does not need to form holes, so that the cost is saved, and the probability of deformation of the copper bar wire is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new energy power battery and energy storage technology, in particular to a manufacturing method of an integrated busbar and the integrated busbar. BACKGROUND

[0002] With the rapid development of the electric vehicle industry, the electrification trend of the powertrain is becoming more and more obvious. The battery, as the power core of the electric vehicle, is a very important part of the entire electric vehicle, and the integrated busbar (Cell Connection System, CCS) is an important part of the battery. The integrated busbar is mainly composed of a signal acquisition component, a plastic structural part, a copper-aluminum bus, etc., which are connected into a whole through processes such as hot pressing or riveting, to realize the functions of high-voltage series and parallel connection of the battery cell, and temperature sampling and battery cell voltage sampling. The signal acquisition component can be a circuit board (FPC flexible circuit board or PCB hard circuit board), FFC (Flat flexible cable), etc.

[0003] At present, the connection methods of FPC and FFC include ultrasonic welding and laser welding. Ultrasonic welding requires a specially made fine welding head, and cracking, perforation and other adverse phenomena may occur during the welding process due to factors such as friction vibration. When laser welding, the molten pool overflows or the metal evaporates to produce metal particles or liquid droplets splashing onto the surface of the component, which may cause risks such as insulation layer rupture and circuit short circuit, reducing product reliability. SUMMARY

[0004] Therefore, the present application provides a manufacturing method of an integrated busbar to improve the connection reliability between the circuit board and the flexible flat cable and improve the reliability of the integrated busbar.

[0005] An embodiment of the present application provides a manufacturing method of an integrated busbar, comprising the following steps:

[0006] forming a blind slot on a circuit board; wherein the circuit board comprises a substrate layer, a circuit layer and a cover film layer, the circuit layer is formed on the surface of the substrate layer, the circuit layer comprises a first electrical connection part and a second electrical connection part, and the cover film layer covers part of the surface of the circuit layer and exposes the first electrical connection part and the second electrical connection part; the blind slot penetrates the substrate layer along the thickness direction of the substrate layer, and the blind slot is arranged corresponding to the first electrical connection part;

[0007] arranging a light-absorbing layer in the blind slot;

[0008] arranging a tin paste on the first electrical connection part, and connecting an electronic component with the second electrical connection part;

[0009] A flexible flat cable includes a copper flat cable and a film layer provided on the copper flat cable, the film layer having an opening, and a portion of a surface of the copper flat cable is exposed from the opening.

[0010] The circuit board is aligned with the flexible flat cable, and the solder paste is accommodated in the opening.

[0011] The solder paste is melted by irradiating the light-absorbing layer with light to connect the first electrical connection portion and the copper flat cable exposed from the opening, thereby connecting the circuit board and the flexible flat cable.

[0012] In one embodiment, the thickness of the light-absorbing layer is 0.2 μm to 2 μm.

[0013] In one embodiment, the light-absorbing layer includes Cu2O and Cu.

[0014] In one embodiment, the wavelength range of the light is 200 nm to 1500 nm.

[0015] In one embodiment, the time of the light irradiation is 3 ms to 4 ms.

[0016] In one embodiment, after the step of "providing solder paste on the first electrical connection portion", the manufacturing method further includes providing a flux on the solder paste.

[0017] One embodiment of the present application provides an integrated busbar including a circuit board, a light-absorbing layer, an electronic component, solder paste, and a flexible flat cable. The circuit board includes a substrate layer, a circuit layer, and a cover film layer, and the circuit layer is formed on a surface of the substrate layer. The circuit layer includes a first electrical connection portion and a second electrical connection portion, and the cover film layer covers a portion of the circuit layer and exposes the first electrical connection portion and the second electrical connection portion. The substrate layer has a blind groove corresponding to the first electrical connection portion. The light-absorbing layer is provided in the blind groove. The electronic component is electrically connected to the second electrical connection portion. The flexible flat cable includes a copper flat cable and a film layer provided on the copper flat cable. The film layer has an opening, and a portion of a surface of the copper flat cable is exposed from the opening. The solder paste is used to connect the first electrical connection portion and the copper flat cable exposed from the opening, thereby connecting the circuit board and the flexible flat cable.

[0018] In one embodiment, the thickness of the light-absorbing layer is 0.2 μm to 2 μm.

[0019] In one embodiment, the light-absorbing layer includes Cu2O and Cu.

[0020] In one embodiment, the film layer includes polyethylene terephthalate.

[0021] The manufacturing method and integrated busbar of the present application set a blind groove on the circuit board, and make the light pass through the blind groove to irradiate on the tin paste arranged correspondingly with the blind groove, so that the tin paste is melted, thereby connecting the circuit board and the flexible flat cable, and the process is simple. At the connecting interface between the tin paste and the copper wire of the flexible flat cable, copper and tin will form a firm intermetallic compound (IMC) (the main component is Cu6Sn5), and the bonding strength is high, which is beneficial to improve the reliability of the integrated busbar. In addition, the light irradiation only acts on the light absorption layer, and other places are not heated, so the PET with cost advantage and low temperature resistance can be selected for the adhesive film layer of the flexible flat cable, and the adhesive film layer away from the welding position does not need to form an opening, which not only saves the cost, but also reduces the probability of deformation of the copper wire. BRIEF DESCRIPTION OF DRAWINGS

[0022] FIG. 1A It is a sectional view of the circuit board of an embodiment of the present application.

[0023] FIG. 1B It is a sectional view of the circuit board shown in FIG. 1A .

[0024] FIG. 1C It is a sectional view of the light absorption layer arranged in the blind groove on the circuit board shown in FIG. 1B .

[0025] FIG. 1D It is a sectional view of the electronic component and tin paste arranged on the circuit board shown in FIG. 1C .

[0026] FIG. 1E It is a sectional view of the flux arranged on the circuit board shown in FIG. 1D .

[0027] FIG. 2 It is a sectional view of the flexible flat cable of an embodiment of the present application.

[0028] FIG. 3 It is a sectional view of the circuit board shown in FIG. 1E and the flexible flat cable shown in FIG. 2 .

[0029] FIG. 4 It is a schematic diagram of the structure shown in FIG. 3 for light curing connection by light irradiation.

[0030] FIG. 5 It is a temperature curve of the circuit board, tin paste and flexible flat cable when light curing connection is performed.

[0031] FIG. 6 It is a sectional view of the integrated busbar obtained after the structure shown in FIG. 4 is light cured in an embodiment.

[0032] FIG. 7 For FIG. 6 a top view of the integrated busbar.

[0033] Main element symbol explanation

[0034] Integrated busbar 100

[0035] Circuit board 10

[0036] Light absorption layer 20

[0037] Solder paste 30

[0038] Electronic component 40

[0039] Flexible flat cable 50

[0040] Light 60

[0041] Photomask plate 70

[0042] Substrate layer 11

[0043] Circuit layer 12

[0044] Cover film layer 13

[0045] Fuse 14

[0046] Soldering flux 31

[0047] Copper cable 51

[0048] Adhesive film layer 52

[0049] Blind groove 101

[0050] First electrical connection part 121

[0051] Second electrical connection part 122

[0052] Aperture 520

[0053] Through hole 701

[0054] The following specific embodiments will further illustrate the embodiments of the present application in conjunction with the above-mentioned drawings. Specific embodiments

[0055] 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 embodiments of the application belong. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of embodiments of the application. Unless specified otherwise, the materials and methods provided herein are those that are conventionally used by those who are skilled in the art. The materials, instruments and manufacturers alphanumerically mentioned in the embodiments are common products available in the market unless otherwise specified.

[0056] It should be noted that all directional indications, such as up, down, left, right, front, back, etc., are merely used for convenience of description and are not intended to limit the application to any particular orientation. It is to be understood that the application can assume various alternative orientations, except where expressly omitted.

[0057] It will be understood that when a layer is referred to as being "on" another layer, it can be directly on the other layer or intervening layers can also be present. In contrast, when a layer is referred to as being "directly on" another layer, there are no intervening layers present. When an element is referred to as being "fixed", "attached", "connected" or "set up" to another element, it can be directly on the other element or intervening elements can also be present. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0058] In addition, throughout this application the use of "a" or "an" to describe a singular quantity also includes the meaning of "one or more" or "at least one", unless otherwise indicated. In addition, the use of "another" to describe a quantity also includes the meaning of "at least a second" or "at least one, but possibly more than one", unless otherwise indicated. Furthermore, the use of the term "about" in describing the application is intended to refer to the approximate value of a quantity, and is not intended to be limited to the exact value of the quantity. In addition, the use of "first", "second", "third", etc. to describe a quantity is not intended to indicate or imply that the quantity is limited to a single quantity, but rather, the quantity can include at least one of the quantity, and can also include more than one of the quantity, unless otherwise indicated.

[0059] Embodiments of the application are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the application. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and / or tolerances, are to be expected. Thus, embodiments of the application should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. The regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the application.

[0060] Some embodiments of the application will now be described in detail in the following description and claims. The following description and claims are not limited to the embodiments described, but extend to any alternative embodiments as can be derived from the description and / or through modification by a person skilled in the art.

[0061] Reference will now be made to FIGS. 1A-7The first aspect of the present application provides a manufacturing method of an integrated busbar 100, comprising steps S10-S60.

[0062] Step S10, referring to FIG. 1A and FIG. 1B a blind slot 101 is formed on the circuit board 10.

[0063] As shown in FIG. 1A , the circuit board 10 comprises a substrate layer 11, a circuit layer 12 and a cover film layer (CVL) 13. The circuit layer 12 is formed on the surface of the substrate layer 11, and the circuit layer 12 comprises a first electrical connection part 121 and a second electrical connection part 122. In some embodiments, the first electrical connection part 121 and the second electrical connection part 122 are referred to as a pad (PAD). The cover film layer 13 covers part of the surface of the circuit layer 12 and part of the surface of the substrate layer 11 exposed from the circuit layer 12. The cover film layer 13 does not cover the first electrical connection part 121 and the second electrical connection part 122, that is, the first electrical connection part 121 and the second electrical connection part 122 can be exposed from the cover film layer 13.

[0064] In this embodiment, the substrate layer 11 and the circuit layer 12 are each only one layer, and in other embodiments, the circuit board 10 can have multiple substrate layers 11 and multiple circuit layers 12, and the substrate layer 11 is located between two adjacent circuit layers 12. It can be understood that when the circuit layer 12 has multiple layers, the cover film layer 13 is arranged on the surface of the outermost circuit layer 12, and the first electrical connection part 121 and the second electrical connection part 122 of the outermost circuit layer 12 are exposed from the cover film layer 13. Moreover, on the side of the circuit board 10 opposite to the cover film layer 13, the outermost layer is the substrate layer 11.

[0065] In some embodiments, the circuit board 10 can be a flexible circuit board or a rigid circuit board, and the present application does not make any limitation. The material of the substrate layer 11 can be, but is not limited to, polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate two formic acid glycol ester (PEN), polydimethylsiloxane (PDMS), liquid crystal polymer (LCP), modified polyimide (MPI), etc. In this embodiment, the material of the substrate layer 11 is PI, and the material of the circuit layer 12 is copper.

[0066] As shown in FIG. 1BAs shown, the blind groove 101 can be formed on the substrate layer 11 by means of, but not limited to, laser. If there are multiple substrate layers 11, the blind groove 101 is formed on the outermost substrate layer 11. The blind groove 101 penetrates the substrate layer 11 along the thickness direction, and part of the surface of the circuit layer 12 can be exposed from the blind groove 101. The position of the blind groove 101 substantially corresponds to the first electrical connection part 121, that is, the orthogonal projection of the blind groove 101 along the thickness direction of the circuit board 10 at least partially overlaps the orthogonal projection of the first electrical connection part 121 along the thickness direction of the circuit board 10. By controlling the laser parameters, the bottom wall of the blind groove 101 can form a rough surface, which increases the surface roughness of the light-absorbing layer 20 (see FIG. 1C ) formed in the subsequent step, thereby increasing the specific surface area of the light-absorbing layer 20.

[0067] In step S20, please refer to FIG. 1C , the light-absorbing layer 20 is arranged in the blind groove 101.

[0068] In some embodiments, the light-absorbing layer 20 can be arranged in the blind groove 101 by electroplating. Since the bottom wall of the blind groove 101 is a rough surface, the surface roughness of the light-absorbing layer 20 formed by electroplating will be increased due to the tip effect, thereby increasing the specific surface area of the light-absorbing layer 20, and further increasing the light absorption.

[0069] In some embodiments, the thickness of the light-absorbing layer 20 can be 0.2 μm to 2 μm to ensure good light absorption effect. The light-absorbing layer 20 includes Cu2O and Cu.

[0070] In step S30, please refer to FIG. 1D , the tin paste 30 is arranged on the first electrical connection part 121, and the electronic component 40 is connected to the second electrical connection part 122.

[0071] In some embodiments, the tin paste 30 can be arranged on the first electrical connection part 121 by printing, and the surface of the tin paste 30 can protrude from the surface of the cover film layer 13 away from the substrate layer 11. The electronic component 40 can be connected to the second electrical connection part 122 by SMT (surface mount technology). The electronic component 40 can be, but is not limited to, an NTC (negative temperature coefficient) thermistor, and the surface of the electronic component 40 can be coated with a glue layer to protect the electronic component 40.

[0072] In some embodiments, please refer to FIG. 1E , after step S30 and before step S40, step S31 of arranging flux 31 on the tin paste 30 can also be performed. The flux 31 has the functions of assisting heat conduction, removing surface dirt and oxides, reducing the surface tension of the connected material, increasing the welding area, preventing re-oxidation, etc. in the subsequent connection process. In another embodiment, step S31 can also be omitted.

[0073] Step S40, referring to FIG. 2 , a flexible flat cable (FFC) 50 is provided. The flexible flat cable 50 includes copper wires 51 and a film layer 52 arranged on the copper wires 51, and the number of the copper wires 51 can be multiple. The film layer 52 can cover the upper and lower surfaces and the side surface of the copper wires 51, and one end of the copper wires 51 can protrude from the film layer 52 along the extension direction of the copper wires 51. The film layer 52 has an opening 520 penetrating through the film layer 52 along the thickness direction of the film layer 52. The side wall of the opening 520 is the film layer 52, and the bottom wall is the copper wire 51, and part of the surface of the copper wire 51 can be exposed from the opening 520.

[0074] In some embodiments, the film layer 52 is polyethylene terephthalate (PET).

[0075] Step S50, referring to FIG. 3 , the circuit board 10 and the flexible flat cable 50 are aligned, and the solder paste 30 is accommodated in the opening 520. Specifically, the circuit board 10 and the flexible flat cable 50 can be stacked in a manner that the circuit board 10 is on the upper side and the flexible flat cable 50 is on the lower side, and the solder paste 30 of the circuit board 10 faces the opening 520 of the flexible flat cable 50, so that the solder paste 30 is accommodated in the opening 520.

[0076] Step S60, referring to FIGS. 4-6 , the light 60 is used to irradiate the light-absorbing layer 20, the light-absorbing layer 20 absorbs the heat of the light 60 and transmits the heat to the solder paste 30 through the first electrical connection part 121, the heat melts the solder paste 30 to connect the first electrical connection part 121 and the copper wire 51 exposed from the opening 520, and then the circuit board 10 and the flexible flat cable 50 are connected, and an integrated busbar as shown in FIG. 6 is obtained. The wavelength range of the light can be 200nm-1500nm, and the wavelength of the light can also be adjusted according to specific needs.

[0077] Specifically, a photomask plate 70 can be arranged on the circuit board 10, and the photomask plate 70 has a through hole 701. The through hole 701 is arranged in alignment with the blind groove 101, and the size of the through hole 701 is substantially the same as the size of the blind groove 101, and the light 60 can pass through the through hole 701 but cannot pass through other areas of the photomask plate 70. In this way, the light irradiation only acts on the light-absorbing layer 20 (i.e. the first electrical connection part 121), and other places are not heated. The film layer 52 of the flexible flat cable 50 is selected to be low-temperature-resistant PET which has cost advantages, and there is no need to select high-temperature-resistant PI material which has high cost. This not only reduces the cost, but also expands the application range of the light irradiation welding.

[0078] Referring to FIG. 5, the light can quickly generate a large amount of heat, and the solder paste 30 only needs 3-4 ms (milliseconds) to melt, the melted solder paste 30 connects the circuit board 10 and the flexible flat cable 50, and the light stops after 3-4 ms. During the entire welding process, the temperature of the flexible flat cable 50 rises relatively small, and the highest temperature is only about 135℃, and the duration is short (seconds), so there is no strict requirement on the heat resistance of the adhesive film layer 52 material selected for the flexible flat cable 50, and low-cost PET can be selected. And even if PET is selected, the light welding method of the present application does not need to open a window (form an opening 520) on the adhesive film layer 52 (PET) away from the circuit board 10. If laser welding is used, the heat affected time is long, and PET is not resistant to high temperature, so before laser welding, the adhesive film layer 52 away from the circuit board 10 also needs to be formed with an opening 520 at the position corresponding to the solder paste 30, the process is complex, and the suspended copper wire 51 is prone to deformation. In the present application, since the light has a small heat effect on PET, the back PET can be retained, and the copper wire 51 can be better supported.

[0079] In the present application, at the connection interface between the solder paste 30 and the copper wire 51, copper and tin will form a firm intermetallic compound (IMC), the main component of which is Cu6Sn5. If the circuit board 10 is also formed of copper, the connection interface between the solder paste 30 and the first electrical connection part 121 will also form an IMC. Compared with ultrasonic welding which only forms a physical connection between two metals, the IMC has high bonding strength, which is beneficial to improve the reliability of the integrated busbar 100. In addition, the light curing welding method of the present application has no mechanical and high frequency vibration, which reduces the risk of cracking of the fuse 14 (see FIG. 7 ) built in the electronic component 40 and the circuit board 10, and also reduces the risk of fracture of the circuit layer 12 and the copper wire 51 at the welding site.

[0080] It can be understood that the step is numbered to clearly describe the specific preparation method, and is not limited to the order of the steps. For example, step S40 can be performed before step S10, or after step S20, or simultaneously with step S10.

[0081] Please refer to FIG. 6 and FIG. 7 , the second aspect of the present application provides an integrated busbar 100 prepared by the above manufacturing method, which comprises a circuit board 10, a light absorbing layer 20, a solder paste 30, an electronic component 40 and a flexible flat cable 50.

[0082] As FIG. 6As shown, the circuit board 10 includes a substrate layer 11, a circuit layer 12, and a cover film layer 13. The circuit layer 12 is formed on the surface of the substrate layer 11, and includes a first electrical connection portion 121 and a second electrical connection portion 122. In some embodiments, the first electrical connection portion 121 and the second electrical connection portion 122 are referred to as pads. The cover film layer 13 covers a portion of the surface of the circuit layer 12 and a portion of the surface of the substrate layer 11 exposed from the circuit layer 12. The cover film layer 13 does not cover the first electrical connection portion 121 and the second electrical connection portion 122; that is, the first electrical connection portion 121 and the second electrical connection portion 122 can be exposed from the cover film layer 13. The substrate layer 11 has a blind groove 101 extending through the substrate layer 11 along its thickness, and the blind groove 101 is disposed corresponding to the first electrical connection portion 121. That is, the orthographic projection of the blind groove 101 along the thickness direction of the circuit board 10 at least partially overlaps with the orthographic projection of the first electrical connection portion 121 along the thickness direction of the circuit board 10.

[0083] In this embodiment, both the substrate layer 11 and the circuit layer 12 are single layers. In other embodiments, the circuit board 10 may have multiple substrate layers 11 and multiple circuit layers 12, with the substrate layer 11 located between two adjacent circuit layers 12. It is understood that when the circuit layers 12 are multiple, a cover film layer 13 is disposed on the surface of the outermost circuit layer 12, and the first electrical connection portion 121 and the second electrical connection portion 122 of the outermost circuit layer 12 are exposed from the cover film layer 13. Furthermore, on the side of the circuit board 10 opposite to the cover film layer 13, the outermost layer is the substrate layer 11, and the outermost substrate layer 11 has a blind groove 101.

[0084] like FIG. 6 As shown, the light-absorbing layer 20 is disposed within the blind groove 101. The thickness of the light-absorbing layer 20 can be 0.2 μm to 2 μm to ensure good light absorption. The light-absorbing layer 20 comprises Cu2O and Cu.

[0085] like FIG. 6 As shown, electronic component 40 is electrically connected to the second electrical connection portion 122. Electronic component 40 may be, but is not limited to, an NTC thermistor. The surface of electronic component 40 may be covered with an adhesive layer to protect electronic component 40.

[0086] like FIG. 6 and FIG. 7 As shown, the flexible flat cable 50 includes copper busbars 51 and an adhesive layer 52 disposed on the copper busbars 51. The number of copper busbars 51 can be multiple. The adhesive layer 52 can cover the upper and lower surfaces and side surfaces of the copper busbars 51. Along the extension direction of the copper busbars 51, one end of the copper busbars 51 can extend out of the adhesive layer 52. The adhesive layer 52 has an opening 520 that penetrates the adhesive layer 52 along its thickness direction. The sidewall of the opening 520 is the adhesive layer 52, and the bottom wall is the copper busbars 51. A portion of the surface of the copper busbars 51 can be exposed through the opening 520.

[0087] In some embodiments, the adhesive layer 52 is PET.

[0088] In some embodiments, the integrated busbar 100 further comprises a conductive busbar (not shown in the figure). The conductive busbar is electrically connected to the circuit board 10, thereby electrically connecting the flexible flat cable 50 and the conductive busbar. The conductive busbar can be, but is not limited to, an aluminum busbar (also known as aluminum bar).

[0089] The manufacturing method and the integrated busbar 100 of the present application connect the circuit board 10 and the flexible flat cable 50 by setting the blind slot 101 on the circuit board 10 and making the light pass through the blind slot 101 to irradiate on the solder paste 30 set corresponding to the blind slot 101, thereby melting the solder paste 30. The process is simple. At the connecting interface between the solder paste 30 and the copper bus 51 of the flexible flat cable 50, copper and tin will form a firm intermetallic compound IMC (mainly composed of Cu6Sn5), which has high bonding strength and is conducive to improving the reliability of the integrated busbar 100. In addition, the light irradiation only acts on the light-absorbing layer 20, and other places are not affected by heat. The adhesive layer 52 of the flexible flat cable 50 can choose low-temperature-resistant PET with cost advantage, and the adhesive layer 52 away from the welding position does not need to form an opening 520, which not only saves cost, but also reduces the probability of deformation of the copper bus 51.

[0090] The above description is some specific embodiments of the present application, but in the actual application process, it cannot be limited to these embodiments only. Other modifications and changes made by those skilled in the art according to the technical concept of the present application should belong to the protection scope of the present application.

Claims

1. A method for manufacturing an integrated busbar, characterized in that, Includes the following steps: A blind slot is formed on a circuit board; wherein the circuit board includes a substrate layer, a circuit layer, and a cover film layer, the circuit layer is formed on the surface of the substrate layer, the circuit layer includes a first electrical connection portion and a second electrical connection portion, the cover film layer covers a portion of the surface of the circuit layer and exposes the first electrical connection portion and the second electrical connection portion; the blind slot penetrates the substrate layer along the thickness direction of the substrate layer, and the blind slot is disposed corresponding to the first electrical connection portion; A light-absorbing layer is provided within the blind groove; Solder paste is applied to the first electrical connection portion, and electronic components are connected to the second electrical connection portion; A flexible flat cable is provided, the flexible flat cable including a copper busbar and an adhesive film layer disposed on the copper busbar, the adhesive film layer having openings, and a portion of the surface of the copper busbar being exposed through the openings; Align the circuit board with the flexible flat cable so that the solder paste is contained within the opening; The light-absorbing layer is irradiated with light to melt the solder paste, thereby connecting the first electrical connection portion and the copper bus exposed from the opening, and connecting the circuit board to the flexible flat cable.

2. The method for manufacturing the integrated busbar as described in claim 1, characterized in that, The thickness of the light-absorbing layer is 0.2 μm to 2 μm.

3. The method for manufacturing the integrated busbar as described in claim 1, characterized in that, The light-absorbing layer comprises Cu2O and Cu.

4. The method for manufacturing the integrated busbar as described in claim 1, characterized in that, The wavelength range of the light is 200nm to 1500nm.

5. The method for manufacturing the integrated busbar as described in claim 1, characterized in that, The duration of light irradiation is 3ms to 4ms.

6. The method for manufacturing the integrated busbar as described in claim 1, characterized in that, After the step of "applying solder paste to the first electrical connection portion", the manufacturing method further includes: applying flux to the solder paste.

7. An integrated busbar, characterized in that, include: A circuit board includes a substrate layer, a circuit layer, and a cover film layer. The circuit layer is formed on the surface of the substrate layer and includes a first electrical connection portion and a second electrical connection portion. The cover film layer covers a portion of the surface of the circuit layer and exposes the first electrical connection portion and the second electrical connection portion. The substrate layer has a blind slot, which is provided corresponding to the first electrical connection portion. A light-absorbing layer is disposed within the blind groove; Electronic components are electrically connected to the second electrical connection portion; A flexible flat cable includes a copper busbar and an adhesive film layer disposed on the copper busbar, the adhesive film layer having openings through which a portion of the surface of the copper busbar is exposed; and Solder paste, used to connect the first electrical connection portion and the copper bus exposed from the opening, thereby connecting the circuit board and the flexible flat cable.

8. The integrated busbar as described in claim 7, characterized in that, The thickness of the light-absorbing layer is 0.2 μm to 2 μm.

9. The integrated busbar as described in claim 7, characterized in that, The light-absorbing layer comprises Cu2O and Cu.

10. The integrated busbar as described in claim 7, characterized in that, The film layer includes polyethylene terephthalate.

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