CN-122002947-A - Stress self-adaptive interconnection method and equipment for thin film battery array based on flexible PCB

CN122002947ACN 122002947 ACN122002947 ACN 122002947ACN-122002947-A

Abstract

The invention relates to the technical field of battery manufacturing, in particular to a stress self-adaptive interconnection method and equipment of a film battery array based on a flexible PCB, wherein the method comprises the steps of forming a micro-groove array on the surface of the PCB and preparing a composite solder structure; collecting the real-time deformation field and the position of a bonding pad of a PCB to generate a compensation mounting path of the thin film battery, controlling the contact force between the thin film battery and the bonding pad to be increased smoothly, carrying out local thermosonic solid-phase bonding on the upper electrode of the thin film battery and the corresponding bonding point on the PCB, forming a high-melting-point intermetallic compound at the position of the lower electrode of the battery and the bonding pad of the PCB by adopting laser irradiation, collecting the three-dimensional shape geometrical parameters of a welding spot, extracting the efficiency distribution and defect characteristics of the battery, dynamically adjusting the upstream technological parameters according to the three-dimensional shape geometrical parameters, calculating the residual stress distribution, and dynamically adjusting the pressure exerted by a hot press roller in different areas in the subsequent packaging technology. The invention can effectively realize the large-scale and high-reliability manufacture of the flexible PCB-based thin film solar wing.

Inventors

Li Lvzhou
DING JIANNING
DONG XU
WEN XIANGLI
JIANG YAOYAO
WANG QIAN

Assignees

扬州大学
扬州大学扬州碳中和技术创新研究中心

Dates

Publication Date: 20260508
Application Date: 20260116

Claims (10)

1. The stress self-adaptive interconnection method of the thin film battery array based on the flexible PCB is characterized by comprising the following steps of: S1, processing a micro-groove array surrounding a bonding pad in a welding area of a flexible PCB, then carrying out laser cleaning and roughening on the surface of the bonding pad, and preparing a composite solder structure containing a low-melting-point metal layer and a high-melting-point metal layer on the bonding pad; S2, acquiring a real-time deformation field and a bonding pad position of the PCB through a vision system, and predicting the PCB deformation in the mounting process by using a deep learning model to generate a compensation mounting path of the thin film battery; S3, mounting a film battery, and controlling the contact force between the film battery and the bonding pad to enable the contact force to smoothly transition from an initial value to a steady-state value; S4, carrying out local thermosonic solid-phase bonding on the bonding points corresponding to the upper electrode of the thin film battery and the PCB, and then, irradiating the lower electrode of the battery and the bonding pad of the PCB with laser to melt the low-melting-point metal layer of the composite solder structure and carrying out diffusion reaction with the high-melting-point metal layer and the copper bonding pad to form a high-melting-point intermetallic compound; s5, collecting the geometric parameters of the three-dimensional morphology of the welding spot, synchronously carrying out electroluminescence and photoluminescence imaging to extract the efficiency distribution and defect characteristics of the battery, and dynamically adjusting the technological parameters in the step S4 through a preset technological mapping model; And S6, calculating residual stress distribution according to the defect characteristics of the battery, and dynamically adjusting the pressure applied by the hot press roller in different areas in the subsequent packaging process to complete interconnection of the thin film battery array.
2. The flexible PCB based thin film battery array stress adaptive interconnection method of claim 1, wherein in step S1, the micro groove array is shaped in a pattern of concentric rings, radial stripes or grid.
3. The stress self-adaptive interconnection method of a flexible PCB-based thin film battery array according to claim 1, wherein in step S2, the deep learning model is a convolutional neural network model, and the compensation mounting path for generating the thin film battery is specifically: Scanning the PCB by using a global camera, and calculating a three-dimensional deformation field of the PCB in the current tensioning state in real time by combining the original size of the PCB; acquiring three-dimensional coordinates of the target bonding pad by using a local camera; Inputting the three-dimensional deformation field of the PCB and the positioning data of the bonding pad into the convolutional neural network model, and calculating deformation prediction vectors of the PCB in three mutually orthogonal directions under the action of mounting force by taking a mounting point on the current bonding pad as a center; and adjusting the originally set mounting path of the thin film battery according to the calculated deformation prediction vector in the three-dimensional direction to form a final compensation mounting path.
4. The stress adaptive interconnection method of flexible PCB-based thin film battery array according to claim 1, wherein in step S3, forces of mounting points in three mutually orthogonal directions and torques in a direction perpendicular to a surface of a bonding pad are measured simultaneously when the thin film battery is mounted, and the forces in the three mutually orthogonal directions are combined to form a contact force.
5. The stress adaptive interconnection method of flexible PCB-based thin film battery array according to claim 1, wherein in step S4, when the local thermosonic solid phase bonding is performed on the bonding points between the electrodes on the thin film battery and the corresponding bonding points on the PCB, the ultrasonic vibration direction is made parallel to the length direction of the PCB.
6. The stress adaptive interconnection method of a flexible PCB-based thin film battery array according to claim 5, wherein in the step S4, when the low melting point metal layer of the composite solder structure is irradiated, pulsed laser is used for irradiation, the wavelength of the pulsed laser corresponds to the absorption peak of the low melting point metal layer of the composite solder, and the spot diameter D of the pulsed laser is greater than 1.2 times the width W of the bonding pad.
7. The flexible PCB based thin film battery array stress adaptive interconnection method of claim 1, wherein in step S5, the three-dimensional topography geometry parameters of the solder joint include height H, volume V and contact angle θ; The process mapping model is a machine learning model trained based on a large amount of experimental data, and establishes quantitative fitting relations among three-dimensional shape geometric parameters of welding spots, thermal ultrasonic solid phase bonding pressure, thermal ultrasonic solid phase bonding time and laser energy density of an irradiated low-melting-point metal layer.
8. A flexible PCB based stress adaptive interconnect device for a thin film battery array, comprising, in order along a material flow direction: A processing module including an ultraviolet laser for fabricating a micro-trench array; The visual force control mounting module comprises an end effector for grabbing a thin film battery through a sucker, a robot for driving the end effector to move and a visual system for shooting PCB images; The interconnection module comprises a thermal ultrasonic solid-phase bonding unit and a laser transient liquid-phase diffusion welding unit which are arranged in parallel in space; The feedback module comprises a laser scanner for collecting geometric parameters of the three-dimensional morphology of the welding spot and an imaging unit for carrying out electroluminescence and photoluminescence imaging; the packaging module comprises a multi-temperature-zone hot-pressing roller set capable of independently controlling temperature and pressure and a packaging film unreeling mechanism; The flexible PCB-based thin film battery array stress adaptive interconnection method further comprises a storage and a processor, wherein the storage is used for storing one or more program instructions, and the processor is used for running the one or more program instructions, controlling the modules and executing the steps of the flexible PCB-based thin film battery array stress adaptive interconnection method according to any one of claims 1-7.
9. The stress self-adaptive interconnection device based on the flexible PCB thin film battery array, which is disclosed in claim 1, is characterized in that the thermal ultrasonic solid phase bonding unit comprises a high-frequency power supply, a piezoelectric transducer, a heating device and a coaxial infrared thermometer, and the selective laser transient liquid phase diffusion welding unit comprises an optical fiber pulse laser, a two-dimensional galvanometer, a coaxial CCD monitoring lens and a protection cavity.
10. The flexible PCB based thin film battery array stress adaptive interconnect device of claim 1, wherein the bottom surface of the suction cup of the end effector is a micro convex surface matching the curvature of the thin film battery and is made of a low thermal conductivity material.

Description

Stress self-adaptive interconnection method and equipment for thin film battery array based on flexible PCB Technical Field The invention relates to the technical field of battery manufacturing, in particular to a stress self-adaptive interconnection method and equipment for a thin film battery array based on a flexible PCB. Background Along with the technical iteration of satellites, the functional requirements on solar wings are also improved, and a flexible PCB is adopted to replace a traditional rigid glass fiber composite substrate or a simple polyimide film, so that the solar wing integrated structure is an ideal scheme for realizing the integrated design of the electrical function, the thermal management function and the light-weight structure of the solar wings. However, achieving high density, high reliability interconnection of thin film gallium arsenide and like cells on flexible PCBs faces a unique set of challenges that conventional electronic assembly processes cannot address: 1. thermal mechanical mismatch, namely, the magnitude order difference exists between the thermal expansion coefficients of the flexible PCB (such as polyimide) and the thin film gallium arsenide battery, and when the solar wing works and is subjected to extreme temperature circulation of-120 ℃ to +120 ℃, huge thermal stress repeatedly acts on interconnection points, and the traditional soldering points are extremely easy to crack and fail due to thermal fatigue, which is a primary factor affecting service life. 2. The high risk of damage to the mounting process is that the thin film battery is only tens to hundreds of microns thick, and extremely fragile. The surface of the flexible PCB is provided with circuit concave-convex, and the battery is easy to break due to uneven contact pressure, scraping with the edge of the circuit or bending moment in the mounting process. 3. The coupling requirement is high, and the mass production is inconvenient, namely, the oxidation tendency of the solder mask layer and copper on the surface of the PCB requires fine pre-welding treatment. The mounting precision directly influences the welding quality, the welding thermal stress influences the packaging reliability, the technological parameters are highly coupled, and the traditional production mode is difficult to adapt to the large-scale production requirement. Disclosure of Invention The invention provides a stress self-adaptive interconnection method and equipment for a flexible PCB-based thin film battery array, which are a complete set of technology from structural design innovation, process principle innovation and equipment control innovation, so that large-scale and high-reliability manufacturing of flexible PCB-based thin film solar wings is realized. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the invention provides a stress self-adaptive interconnection method of a thin film battery array based on a flexible PCB, which comprises the following steps: S1, processing a micro-groove array surrounding a bonding pad in a welding area of a flexible PCB, then carrying out laser cleaning and roughening on the surface of the bonding pad, and preparing a composite solder structure containing a low-melting-point metal layer and a high-melting-point metal layer on the bonding pad; S2, acquiring a real-time deformation field and a bonding pad position of the PCB through a vision system, and predicting the PCB deformation in the mounting process by using a deep learning model to generate a compensation mounting path of the thin film battery; S3, mounting a film battery, and controlling the contact force between the film battery and the bonding pad to enable the contact force to smoothly transition from an initial value to a steady-state value; S4, carrying out local thermosonic solid-phase bonding on the bonding points corresponding to the upper electrode of the thin film battery and the PCB, and then, irradiating the lower electrode of the battery and the bonding pad of the PCB with laser to melt the low-melting-point metal layer of the composite solder structure and carrying out diffusion reaction with the high-melting-point metal layer and the copper bonding pad to form a high-melting-point intermetallic compound; s5, collecting the geometric parameters of the three-dimensional morphology of the welding spot, synchronously carrying out electroluminescence and photoluminescence imaging to extract the efficiency distribution and defect characteristics of the battery, and dynamically adjusting the technological parameters in the step S4 through a preset technological mapping model; And S6, calculating residual stress distribution according to the defect characteristics of the battery, and dynamically adjusting the pressure applied by the hot press roller in different areas in the subsequent packaging process to complete interconnection of the thin film battery array. Further, in step