CN114406391A - Welding method for aluminum-based flexible circuit board and component - Google Patents

Abstract

The invention discloses a method for welding an aluminum-based flexible circuit board and a component, which comprises the following steps: carrying out surface treatment on the original aluminum-based flexible circuit board to obtain a treated aluminum-based flexible circuit board; pre-coating tin-based solder on the treated aluminum-based flexible circuit board to obtain a target aluminum-based flexible circuit board; and carrying out laser soldering on the target aluminum-based flexible circuit board and the component to be soldered to complete soldering. The influence of an oxide film on the surface of the aluminum-based flexible circuit board is removed through surface treatment, and the wettability of the joint is improved; by pre-coating tin-based brazing filler metal and introducing a laser soldering method, the problems of long welding time, low efficiency and high energy consumption caused by reflow soldering are solved on the basis of ensuring that the micron-sized aluminum substrate and the copper-based component are effectively connected, the pressure sensitivity and the temperature sensitivity in the traditional welding method are overcome, the high-efficiency and high-quality connection of the aluminum-based flexible circuit board and the component is realized, and the aluminum-based flexible circuit board can be further popularized and applied.

Description

A kind of welding method of aluminum-based flexible circuit board and components

technical field

The invention relates to the fields of electronic packaging and automobiles, in particular to a welding method of an aluminum-based flexible circuit board and components.

Background technique

The traditional FPC (Flexible Printed Circuit, flexible circuit board) industry mostly uses copper-based circuit boards (including PCB and FPCB), but due to aluminum's good electrical conductivity, thermal conductivity, light weight (30% of copper) and low cost (copper 1/6) of the obvious advantages, which can greatly reduce the cost and effectively reduce the weight of the vehicle, and ultimately improve fuel economy and reduce emissions to achieve carbon emission reduction. Therefore, in the application of the automotive industry, especially the new energy electric vehicle industry, aluminum substrates are expected to replace traditional copper-based circuit boards, thereby greatly reducing production costs while increasing cruising range and reducing energy consumption.

In the prior art, in the first aspect, the technology for soldering components (most of their pins or solder joints are copper-based) on the surface of traditional copper-based flexible circuit board pads is very mature (mainly by reflow soldering). However, since the number of components (solder joint area) that needs to be connected on the surface of the vehicle circuit board is very small compared to the entire circuit board area, the reflow soldering method brings the problems of long soldering time, low efficiency and energy waste. Therefore, it is not recommended to apply the reflow soldering method to the soldering of aluminum-based flexible circuit boards and copper-based components.

On the other hand, when the copper substrate is replaced with an aluminum substrate, since there is an aluminum oxide (Al ₂ O ₃ ) oxide film on the surface of the aluminum substrate and it is difficult to remove, this dense high melting point aluminum oxide film makes the aluminum-based flexible circuit board Difficult to wet with tin-based solder to form a good solder joint. In order to improve the wettability of the joint, the prior art mainly utilizes the welding method of chemical reaction. This method uses NaOH solution to first remove the Al ₂ O ₃ oxide film on the surface of the aluminum substrate by alkaline etching, and then use HNO ₃ to passivate the surface. Apply solder paste immediately after HNO ₃ passivation and then reflow soldering, which can minimize the thickness of Al ₂ O ₃ oxide film. At the same time, adding Zn, Ga and Na to the solder paste makes the solder paste alloy, which can effectively improve the Wettability of the joint. However, due to the need to add alloying elements and the Al ₂ O ₃ oxide film cannot be completely removed in this method, the Al ₂ O ₃ oxide film still exists in local areas, which may lead to false welding in these local areas. Therefore, this method inevitably brings The cost is increased and the safe service performance of the joint is uncontrollable. In addition, because this method still uses traditional reflow soldering, its efficiency has not been improved, and it is not suitable for the welding of aluminum-based flexible circuit boards and copper-based components.

In the third aspect, the welding of aluminum-based flexible circuit boards and copper-based components is actually a connection problem of micron-level copper and aluminum. The connection method of micron-level copper and aluminum reported in cutting-edge literature and technology is mainly solid-phase welding ( Including friction stir welding, ultrasonic welding and other methods) and nano-laser welding. For solid-phase welding, such as ultrasonic welding, this method uses ultrasonic waves to break the oxide film on the surface of the aluminum substrate to form a connection, but the aluminum substrate is millimeter-level, while the thickness of the flexible circuit board is micrometer-level and is extremely sensitive to pressure. The size effect of circuit boards and components (<100μm), in the actual operation process, there are difficult problems such as difficult tooling, high pressure and easy damage to the circuit board. Therefore, this method is also not suitable for the welding of aluminum-based flexible circuit boards and copper-based components. For nano-laser welding, it can effectively connect the micron-scale aluminum substrate and copper plate, but based on the high energy density of nano-laser, the welding joint will inevitably have defects formed after laser ablation, which will greatly reduce the flexible circuit. Therefore, it is not recommended to be used in the welding of aluminum-based flexible circuit boards and copper-based components.

In summary, how to achieve efficient and high-quality connection between aluminum-based flexible circuit boards and components is a bottleneck problem that restricts the further promotion and application of aluminum-based flexible circuit boards.

SUMMARY OF THE INVENTION

In view of this, the embodiment of the present invention provides a welding method of an aluminum-based flexible circuit board and a component, so as to solve the problem that the oxide film on the surface of the aluminum-based flexible circuit board in the prior art hinders the welding of the aluminum-based flexible circuit board and the solder. Reactive wetting, the high temperature sensitivity and pressure sensitivity of aluminum-based flexible circuit boards during the soldering process, and the long soldering time, low efficiency and high energy consumption caused by traditional reflow soldering methods can achieve aluminum-based flexible circuit boards. High-efficiency and high-quality connection between circuit boards and components, so that aluminum-based flexible circuit boards can be further popularized and used.

The embodiment of the present invention provides a welding method for an aluminum-based flexible circuit board and a component, including:

Surface treatment of the original aluminum-based flexible circuit board to obtain a treated aluminum-based flexible circuit board;

Pre-applying tin-based solder to the treated aluminum-based flexible circuit board to obtain a target aluminum-based flexible circuit board;

Laser soldering is performed on the target aluminum-based flexible circuit board and the components to be welded to complete the welding.

Optionally, the surface treatment of the original aluminum-based flexible circuit board includes:

Perform degreasing treatment and alkali etching treatment on the original aluminum-based flexible circuit board in sequence to obtain a first aluminum-based flexible circuit board;

Using pure water, the first aluminum-based flexible circuit board is cleaned to obtain a second aluminum-based flexible circuit board.

Optionally, after cleaning the first aluminum-based flexible circuit board, the method further includes:

chemically dipping the second aluminum-based flexible circuit board to obtain a third aluminum-based flexible circuit board;

Nickel plating is performed on the third aluminum-based flexible circuit board to obtain the treated aluminum-based flexible circuit board.

Optionally, the thickness of the nickel plating ranges from 4 to 7 μm.

Optionally, the thickness of the nickel plating ranges from 5 to 6 μm.

Optionally, before pre-applying tin-based solder to the processed aluminum-based flexible circuit board, the method further includes:

performing ultrasonic cleaning on the treated aluminum-based flexible circuit board;

Air-drying is performed on the treated aluminum-based flexible circuit board after ultrasonic cleaning.

Optionally, the thickness of the tin-based solder is in the range of 15-20 μm.

Optionally, performing laser soldering on the target aluminum-based flexible circuit board and the components to be welded includes:

fixing the target aluminum-based flexible circuit board;

placing the pins of the components to be welded above the fixed target aluminum-based flexible circuit board, and fixing the components to be welded;

Using laser soldering equipment, the fixed target aluminum-based flexible circuit board and the fixed pins of the components to be welded are welded.

Optionally, the laser spot emitted by the laser welding device coincides with the center of the pin of the component to be welded.

Optionally, the diameter of the welding wire provided by the laser welding equipment ranges from 0.3 to 0.6 mm.

Optionally, in the welding of the target aluminum-based flexible circuit board and the pins of the component to be welded, the process further includes:

Infrared temperature detection equipment is used to detect the welding temperature between the target aluminum-based flexible circuit board and the pins of the component to be welded in real time; wherein, the welding temperature is less than 500°C.

Beneficial effects of the present invention:

By surface treatment of the original aluminum-based flexible circuit board, on the one hand, the influence of the oxide film on the surface of the aluminum-based flexible circuit board can be removed, thereby preventing the oxide film from hindering the reaction and wetting of the aluminum-based flexible circuit board and the solder, and improving the wetting of the joint. On the other hand, the traditional reflow soldering method can be avoided to ensure the high efficiency of soldering; by pre-applying tin-based solder to the processed aluminum-based flexible circuit board, it is easy to use the tin-based solder to melt, and separately and the components The copper pins and the nickel layer form a good metallurgical combination, which realizes the efficient and high-quality connection between the aluminum-based flexible circuit board and the copper-based components; based on the tin-based solder, in the welding of the target aluminum-based flexible circuit board and the components to be welded The introduction of the laser soldering method can solve the problems of long welding time, low efficiency and high energy consumption caused by reflow soldering on the basis of ensuring the effective connection between the micron-scale aluminum substrate and the copper-based components, and further reduce the production cost. At the same time, it promotes the realization of carbon peaking and carbon neutralization; on the one hand, it can avoid the pressure sensitivity in traditional solid-phase welding methods, and there will be no problems such as difficult tooling and easy damage to circuit boards under high pressure. On the other hand, it can overcome the The temperature sensitivity in the traditional nano-laser welding method will not cause laser ablation to form defects and reduce the service safety performance of the flexible circuit board;

The welding method of the aluminum-based flexible circuit board and the components in the present invention can effectively solve the problem that the oxide film on the surface of the aluminum-based flexible circuit board in the prior art hinders the reaction wetting of the aluminum-based flexible circuit board and the solder, and the aluminum-based flexible circuit board The high temperature sensitivity and pressure sensitivity of the circuit board during the soldering process, as well as the long soldering time, low efficiency and high energy consumption caused by the traditional reflow soldering method, can realize the high efficiency of aluminum-based flexible circuit boards and components. High-quality connection, so that the aluminum-based flexible circuit board can be further popularized and used.

Description of drawings

The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way, in which:

FIG. 1 shows a flowchart of a welding method for an aluminum-based flexible circuit board and components in an embodiment of the present invention;

FIG. 2 shows a flow chart of obtaining and processing an aluminum-based flexible circuit board in an embodiment of the present invention;

FIG. 3 shows a flow chart of the steps before processing the aluminum-based flexible circuit board with tin-based solder in an embodiment of the present invention;

4-1 shows the SEM surface topography of the target aluminum-based flexible circuit board in the embodiment of the present invention;

Figure 4-2 shows an enlarged view of the dashed box in Figure 4-1;

5 shows a cross-sectional structural model diagram of a target aluminum-based flexible circuit board in an embodiment of the present invention;

6 shows a flowchart of laser soldering a target aluminum-based flexible circuit board and components to be welded in an embodiment of the present invention;

FIG. 7 shows a model diagram of laser soldering in an embodiment of the present invention.

The description of each reference number is as follows:

100, target aluminum-based flexible circuit board, 110, original aluminum-based flexible circuit board, 120, nickel layer, 130, tin-based solder, 200, components to be welded, 210, copper pins, 300, laser welding equipment, 310 , Laser, 311, laser spot, 320, wire feeder, 321, welding wire.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

An embodiment of the present invention provides a welding method for an aluminum-based flexible circuit board and components, as shown in FIG. 1 , including:

S10, performing surface treatment on the original aluminum-based flexible circuit board to obtain a treated aluminum-based flexible circuit board;

S20, pre-applying tin-based solder to the treated aluminum-based flexible circuit board to obtain a target aluminum-based flexible circuit board;

S30, laser soldering is performed on the target aluminum-based flexible circuit board and the components to be welded to complete the welding.

Specifically, in this embodiment S10 , a 100 μm aluminum-based flexible circuit board (with a polyimide film thickness of 20 μm) is selected as the original aluminum-based flexible circuit board for surface treatment.

Preferably, as shown in Figure 2, step S10 includes:

S101: Perform degreasing treatment and alkali etching treatment on the original aluminum-based flexible circuit board in sequence to obtain a first aluminum-based flexible circuit board;

S102: using pure water to clean the first aluminum-based flexible circuit board to obtain a second aluminum-based flexible circuit board;

S103: chemically dipping the second aluminum-based flexible circuit board to obtain a third aluminum-based flexible circuit board;

S104: Perform nickel plating on the third aluminum-based flexible circuit board to obtain the treated aluminum-based flexible circuit board.

Degreasing treatment and alkaline etching treatment are carried out in sequence to remove the metal oxide film on the surface of the original aluminum-based flexible circuit board, thereby avoiding the adverse effects of the inert metal oxide film, which is convenient for the formation of components and aluminum-based flexible circuit boards. Solder joints with no defects and excellent performance; through the cleaning of pure water, the residual alkaline solution on the surface of the first aluminum-based flexible circuit board can be cleaned, and at the same time, the surface of the second aluminum-based flexible circuit board obtained after cleaning It is possible to isolate the aluminum surface from contact with the air to generate a new oxide film; through chemical galvanization, it can further ensure that the surface of the third aluminum-based flexible circuit board obtained is a Zn layer instead of an Al ₂ O ₃ oxide film, and the aluminum-based flexible circuit board The Al ₂ O ₃ oxide film on the surface is completely eliminated and a barrier layer is formed to prevent the formation of the Al ₂ O ₃ oxide film, further effectively avoiding the adverse effects of the metal oxide film; by plating nickel on the surface of the third aluminum-based flexible circuit board , which can ensure that the surface of the aluminum-based flexible circuit board finally obtained after surface treatment has a good bonding force, which helps components and aluminum-based flexible circuit boards to form defect-free and excellent performance welding joints.

Specifically, in this embodiment S101, alcohol or acetone is used to degreasing the original aluminum-based flexible circuit board, and 20% NaOH solution is selected to soak for 3-5 minutes to soak the original aluminum-based flexible circuit board after the degreasing treatment. , the soaking time is 3 to 5 minutes, and the alkaline etching treatment is completed. In the present embodiment S102, after the original aluminum-based flexible circuit board is subjected to degreasing treatment and alkali etching treatment, the obtained first aluminum-based flexible circuit board is immediately put into pure water, which can clean the 20% NaOH solution remaining on the surface. At this time, the residual water film on the surface of the aluminum-based flexible circuit board can isolate the aluminum surface from contact with the air to the greatest extent and form a new oxide film. In this embodiment S103, the second aluminum-based flexible circuit board obtained after cleaning is immediately put into a zincate solution for chemical immersion zinc, and the concentration ratio of the zincate solution can be set and adjusted according to the actual situation.

Among them, the chemical reaction equation of chemical immersion zinc is: 2Al+3Zn ²⁺ →3Zn+2Al ³⁺ .

Specifically, in the present embodiment S104, the thickness of the nickel plating is in the range of 4-7 μm, and preferably, the thickness of the nickel plating is in the range of 5-6 μm.

According to the above thickness range, nickel plating can ensure that the Ni plating layer on the surface of the aluminum-based flexible circuit board has good bonding force, and on the other hand, it can avoid the cost increase caused by the large thickness of the Ni plating layer.

Preferably, as shown in FIG. 3, before S20, it also includes:

S201: performing ultrasonic cleaning on the treated aluminum-based flexible circuit board;

S202 : drying the treated aluminum-based flexible circuit board after ultrasonic cleaning.

Specifically, in the present embodiment S201, using absolute ethanol to ultrasonically clean the processed aluminum-based flexible circuit board can ensure the integrity and cleanliness of the nickel film on the surface of the processed aluminum-based flexible circuit board.

Specifically, in the present embodiment S20, the thickness of the tin-based solder is in the range of 15-20 μm.

In order to ensure that the aluminum-based flexible circuit board has a certain rigidity, a layer of polyimide board (ie PI board) is often attached to the back of the board. In this embodiment, the tin-based solder in the above thickness range can ensure the tin-based The solder absorbs the heat of the laser radiation, so that the heat will not cause discoloration of the PI board when the heat is transmitted to the PI board; on the other hand, it can avoid the increase in cost caused by the large thickness of tin-based solder, and also avoid increasing the uneven solidification of the solder. and increase the laser irradiation time, thus ensuring the high efficiency of welding.

More specifically, the thickness of nickel plating in this embodiment is 5 μm, and the tin-based solder is SAC305, and the thickness is 18 μm. As shown in Figure 4-1 and Figure 4-2, Figure 4-1 is the SEM (Scanning Electron Microscope) surface topography of the target aluminum-based flexible circuit board after plating with 5μm nickel layer and 18μm tin-based solder, respectively. Figure 4-2 is an enlarged view of the dotted box in Figure 4-1. By observing the surface topography image obtained by scanning electron microscope, it can be found that after plating a 5 μm nickel layer, the nickel layer is evenly distributed along the upper side of the aluminum and there is no black nickel phenomenon. After plating 18μm tin-based solder, the entire tin layer is composed of tin grains of different sizes and shapes. The entire tin layer is evenly distributed on the nickel layer, and there are no defects such as cracks and holes.

The model diagram of the target aluminum-based flexible circuit board 100 obtained after surface treatment, nickel-plating and tin-based soldering in this embodiment is shown in FIG. 5 . In FIG. 5 , the surface of the original aluminum-based flexible circuit board 110 is plated with nickel. The nickel layer 120 is plated with a tin-based solder 130 .

Preferably, as shown in Figure 6, S30 includes:

S301: Fix the target aluminum-based flexible circuit board;

S302: Place the pins of the components to be welded above the fixed target aluminum-based flexible circuit board, and fix the components to be welded;

S303: Use laser soldering equipment to weld the fixed target aluminum-based flexible circuit board and the fixed pins of the component to be welded.

Specifically, the model diagram of laser welding in this embodiment is shown in FIG. 7 . In FIG. 7 , the laser soldering equipment 300 is produced by Dr. Mergenthaler GmbH & Co. KG in Germany. The diameter of the ring light source is 0.7 mm, including the laser 310 and wire feeder 320. The laser 310 is a semiconductor laser with a full power of 60W and a wavelength of 970nm. The laser spot 311 emitted by the semiconductor laser coincides with the center of the copper pin 210 of the component 200 to be welded. The wire feeder 320 provides the welding wire 321, the welding wire is a tin-based welding wire, and the diameter of the welding wire is 0.3-0.6 mm; more specifically, the tin-based welding wire is a lead-free F3 M705 (Sn-3Ag-0.5Cu) welding wire of 0.3 mm. The wire feeder 320 is an existing wire feeder, and details are not repeated here.

Use a soldering fixture to fix the target aluminum-based flexible circuit board on the workbench. The components to be soldered are 8-SOIC (0.154", 3.90mm wide) general-purpose amplifiers. Place the pins to be soldered on the target The aluminum-based flexible circuit board is placed above the position of the pre-tin-based solder, and fixed with a welding fixture to prevent deviation during the welding process. The components to be welded usually have multiple pins that need to be welded with the target aluminum-based flexible circuit board. , in the welding process of each pin, the laser spot emitted by the laser welding equipment needs to be overlapped with the center of the pin of the component to be welded, so as to ensure a good welding effect. For some welding tools, the specific details will not be repeated here.

In the process of laser soldering, the semiconductor laser first starts the radiation to heat up and preheat the pins of the components to be welded, and then the tin-based welding wire is fed under the action of the wire feeder and melted under the radiation of the laser emitted by the semiconductor laser. The formed droplets fall on the copper pins of the components to be welded. At the same time as the droplets form and drop, the tin-based welding wire is pulled back under the pullback action of the wire feeder, the semiconductor laser is turned off at the same time, and the welding is completed.

In the above-mentioned laser soldering process, the molten tin-based welding wire forms droplets and drops on the copper pins, and the heat is further transferred to the tin-based solder under the pins through thermal conduction, so that the solder melts and separates with the pins. It forms a good metallurgical combination with the nickel layer, and finally can obtain high-quality components and welding joints of aluminum-based flexible circuit boards. The mechanical properties of the obtained welded joint depend on the bonding ability of the nickel layer and the aluminum-based flexible circuit board and the metallurgical bonding ability of the welding wire with the nickel layer and the pins after melting, which fundamentally solves the problem of the inert oxide film on the surface of the aluminum-based flexible circuit board. The adverse effects brought about by the components and aluminum-based flexible circuit boards can form defect-free and excellent solder joints.

Preferably, in S303, it also includes:

Infrared temperature detection equipment is used to detect the welding temperature between the target aluminum-based flexible circuit board and the pins of the component to be welded in real time; wherein, the welding temperature is less than 500°C.

By detecting the welding temperature between the target aluminum-based flexible circuit board and the pins of the components to be welded in real time, and requiring the welding temperature to be less than 500 °C, it can ensure that the temperature tolerance range of the PI board and the entire The temperature sensitivity range of aluminum-based flexible circuit boards can avoid laser ablation to form defects and reduce the service safety performance of flexible circuit boards.

In a specific embodiment, the entire laser welding process in S303 is divided into five steps. The first step is that the laser starts to irradiate the copper pins of the component to be welded, and the temperature in the circular laser irradiation area is raised to T1 within 0.1s; the second step is the continuous laser irradiation, so that the circular laser irradiation The temperature in the area is maintained for t1 under T1 to achieve preheating; the third step is to continue to irradiate the laser, and make the temperature in the circular laser irradiation area within t1, from T1 to the peak temperature T2; The fourth step is to continuously irradiate the laser, so that the temperature in the circular laser irradiation area is maintained at T2 for a length of t2, and at the same time, the wire feeder starts to feed the wire; the fifth step is to stop the wire feeding when the time reaches t3. And the laser stops irradiating to complete the welding. After several sets of tests, it was found that when the peak temperature T2 ≥ 500 °C, the PI board at the bottom of the aluminum-based flexible circuit board is prone to discoloration due to thermal conduction, as shown in the following table. Therefore, the welding temperature in the actual laser soldering process should be less than 500 °C.

Table Discoloration of the PI board at the bottom of the aluminum-based flexible circuit board at different peak temperatures

Specifically, in this embodiment S303, suitable parameters are selected for laser soldering, including T1=140°C, T2=342°C, t1=0.1s, t2=0.36s, t3=0.66s. Under this parameter, nickel-plating and tin-plating-based solder were performed according to the steps of the present invention, and the upper surface forming and cross-sectional morphology of the aluminum-based flexible circuit board and the laser tin welding joint of the components to be welded were compared and observed. It was found that the tin-based solder without tin plating on the surface did not spread and connect around the copper pins, but solidified and shrunk into a spherical shape on the copper pins, and the copper pins did not form an effective connection with the aluminum-based flexible circuit board. The tin-based solder is agglomerated on the copper pins and does not fully spread and wet; while the tin-plated aluminum-based flexible circuit board forms an effective connection with the components to be soldered, and the entire tin-based solder does not agglomerate and shrink on the copper pins. Instead, it is fully wetted and spread on the aluminum substrate and copper pins.

Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, various modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the present invention, such modifications and variations falling within the scope of the appended claims within the limited range.

Claims (10)

1. A method for welding an aluminum-based flexible circuit board and a component is characterized by comprising the following steps:

carrying out surface treatment on the original aluminum-based flexible circuit board to obtain a treated aluminum-based flexible circuit board;

pre-coating tin-based brazing filler metal on the treated aluminum-based flexible circuit board to obtain a target aluminum-based flexible circuit board;

and carrying out laser soldering on the target aluminum-based flexible circuit board and the component to be welded to finish welding.

2. The method for welding the aluminum-based flexible circuit board and the component as claimed in claim 1, wherein the surface treatment of the original aluminum-based flexible circuit board comprises:

sequentially carrying out oil removal treatment and alkaline etching treatment on the original aluminum-based flexible circuit board to obtain a first aluminum-based flexible circuit board;

and cleaning the first aluminum-based flexible circuit board by adopting purified water to obtain a second aluminum-based flexible circuit board.

3. The method for soldering the aluminum-based flexible circuit board and the component as claimed in claim 2, further comprising, after the first aluminum-based flexible circuit board is cleaned:

chemically zincating the second aluminum-based flexible circuit board to obtain a third aluminum-based flexible circuit board;

and carrying out nickel plating on the third aluminum-based flexible circuit board to obtain the treated aluminum-based flexible circuit board.

4. The method for welding the aluminum-based flexible circuit board and the component as claimed in claim 3, wherein the thickness of the nickel plating is 5-6 μm.

5. A method for soldering an al-based flexible wiring board and a component as claimed in claim 1, wherein before the pre-application of the tin-based solder to the processed al-based flexible wiring board, the method further comprises:

carrying out ultrasonic cleaning on the aluminum-based flexible circuit board to be treated;

and carrying out air drying treatment on the aluminum-based flexible circuit board after ultrasonic cleaning.

6. The method for welding the aluminum-based flexible circuit board and the component as claimed in claim 1, wherein the thickness of the tin-based solder is in a range of 15 to 20 μm.

7. The method for welding the aluminum-based flexible circuit board and the component according to claim 1, wherein the laser soldering of the target aluminum-based flexible circuit board and the component to be welded comprises:

fixing the target aluminum-based flexible circuit board;

placing the pin of the component to be welded above the fixed target aluminum-based flexible circuit board, and fixing the component to be welded;

and welding the fixed target aluminum-based flexible circuit board and the fixed pin of the component to be welded by adopting laser soldering equipment.

8. The method for welding the aluminum-based flexible circuit board and the component as claimed in claim 7, wherein a laser spot emitted by the laser welding equipment coincides with the center of a pin of the component to be welded.

9. The welding method of the aluminum-based flexible circuit board and the component as claimed in claim 7, wherein the diameter range of the welding wire provided by the laser welding equipment is 0.3-0.6 mm.

10. The method for soldering the aluminum-based flexible circuit board and the component according to claim 7, wherein in soldering the target aluminum-based flexible circuit board and the pin of the component to be soldered, the method further comprises:

detecting the welding temperature between the target aluminum-based flexible circuit board and the pin of the component to be welded in real time by adopting infrared temperature detection equipment; wherein the welding temperature is less than 500 ℃.

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