Process Monitoring in Ultrasonic Metal Welding of Lithium Batteries by Power Signals

2021 ◽  
pp. 1-22
Author(s):  
Xinhua Shi ◽  
Lin Li ◽  
Suiran Yu ◽  
Lingxiang Yun
Keyword(s):  
Electric Power ◽  
Process Monitoring ◽  
Lithium Batteries ◽  
Welding Process ◽  
Ultrasonic Metal Welding ◽  
Isometric Transformation ◽  
Welding Defects ◽  
Different Types ◽  
Metal Welding ◽  
Welding Processes

Abstract Ultrasonic metal welding is one of the key technologies in manufacturing lithium batteries, and the welding quality directly determines the battery performance. Therefore, an online welding process monitoring system is critical in identifying abnormal welding processes, detecting defects, and improving battery quality. Traditionally, the peak welding power is used to indicate abnormal process signals in welding process monitoring systems. However, since various factors have complex impacts on the electric power signals of ultrasonic welding processes, the peak power is inadequate to detect different types of welding defects. Therefore, a signal pattern matching method is proposed in this study, which is based on the electric power signal during the entire welding process and thus is capable of identifying abnormal welding processes in various conditions. The proposed method adopts isometric transformation and homogenization as signal pretreatment methods, and Euclidean distance is used to calculate the similarity metric for signal matching. The effectiveness and robustness of the proposed method are experimentally validated under different abnormal welding conditions.

Dynamics of Battery Tabs Under Ultrasonic Welding

2013 ◽  
Author(s):  
Bongsu Kang ◽  
Wayne Cai ◽  
Chin-An Tan
Keyword(s):  
Longitudinal Vibration ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Point Of View ◽  
Structural Vibration ◽  
Kinetic Properties ◽  
Weld Quality ◽  
Ultrasonic Metal Welding ◽  
Metal Welding ◽  
Welding Processes

Ultrasonic metal welding for battery tabs must be performed with 100% reliability in battery pack manufacturing as the failure of a single weld essentially results in a battery that is inoperative or cannot deliver the required power due to the electrical short caused by the failed weld. In ultrasonic metal welding processes, high-frequency ultrasonic energy is used to generate an oscillating shear force (sonotrode force) at the interface between a sonotrode and few metal sheets to produce solid-state bonds between the sheets clamped under a normal force. These forces, which influence the power needed to produce the weld and the weld quality, strongly depend on the mechanical and structural properties of the weld parts and fixtures in addition to various welding process parameters such as weld frequencies and amplitudes. In this work, the effect of structural vibration of the battery tab on the required sonotrode force during ultrasonic welding is studied by applying a longitudinal vibration model for the battery tab. It is found that the sonotrode force is greatly influenced by the kinetic properties, quantified by the equivalent mass and equivalent stiffness, of the battery tab and cell pouch interface. This study provides a fundamental understanding of battery tab dynamics during ultrasonic welding and its effects on weld quality, and thus provides useful guidelines for design and welding of battery tabs from tab dynamics point of view.

Dynamic Response of Battery Tabs Under Ultrasonic Welding

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Bongsu Kang ◽  
Wayne Cai ◽  
Chin-An Tan
Keyword(s):  
Longitudinal Vibration ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Structural Vibration ◽  
Kinetic Properties ◽  
Weld Quality ◽  
Equivalent Viscous Damping ◽  
Ultrasonic Metal Welding ◽  
Metal Welding ◽  
Welding Processes

Ultrasonic metal welding (USMW) for battery tabs must be performed with 100% reliability in battery pack manufacturing as the failure of a single weld essentially results in a battery that is inoperative or cannot deliver the required power due to the electrical short caused by the failed weld. In ultrasonic metal welding processes, high-frequency ultrasonic energy is used to generate an oscillating shear force (sonotrode force) at the interface between a sonotrode and few metal sheets to produce solid-state bonds between the sheets clamped under a normal force. These forces, which influence the power needed to produce the weld and the weld quality, strongly depend on the mechanical and structural properties of the weld parts and fixtures in addition to various welding process parameters, such as weld frequencies and amplitudes. In this work, the effect of structural vibration of the battery tab on the required sonotrode force during ultrasonic welding is studied by applying a longitudinal vibration model for the battery tab. It is found that the sonotrode force is greatly influenced by the kinetic properties, quantified by the equivalent mass, equivalent stiffness, and equivalent viscous damping, of the battery tab and cell pouch interface. This study provides a fundamental understanding of battery tab dynamics during ultrasonic welding and its effect on weld quality, and thus provides a guideline for design and welding of battery tabs from tab dynamics point of view.

Ultrasonic Rapid Manufacturing: Implementation and Thermo-Mechanical Analysis

2002 ◽  
Author(s):  
Shailendra Yadav ◽  
Charalabos Doumanidis
Keyword(s):  
Temperature Effects ◽  
Welding Process ◽  
Mechanical Analysis ◽  
Ultrasonic Welding ◽  
Solid Metal ◽  
Rapid Manufacturing ◽  
Mechanical Process ◽  
Ultrasonic Metal Welding ◽  
Metal Parts ◽  
Metal Welding

This paper addresses a novel non-thermal Ultrasonic Rapid Manufacturing (URM), for layered parts based on Ultrasonic Metal Welding (USW). Its laboratory implementation, automation and integration are described first. The thermo-mechanical process aspects (i.e. heat generation and resulting temperature effects) during each cycle of ultrasonic welding are then studied. The technical advantages of ultrasonic welding process, including fabrication of dense, full-strength functional solid metal parts, multi-material composites, and active parts with embedded intelligent components and electronic, mechatronic, optic and fluidic structures, are examined.

scholarly journals Process monitoring of ultrasonic metal welding of battery tabs using external sensor data

2020 ◽  
Vol 1 ◽  
pp. 100005
Author(s):  
I. Balz ◽  
E. Abi Raad ◽  
E. Rosenthal ◽  
R. Lohoff ◽  
A. Schiebahn ◽  
...  
Keyword(s):  
Process Monitoring ◽  
Sensor Data ◽  
Ultrasonic Metal Welding ◽  
Metal Welding

Characterization of Joint Quality in Ultrasonic Welding of Battery Tabs

2012 ◽  
Author(s):  
S. Shawn Lee ◽  
Tae H. Kim ◽  
S. Jack Hu ◽  
Wayne W. Cai ◽  
Jingjing Li ◽  
...  
Keyword(s):  
Lithium Ion ◽  
Ultrasonic Welding ◽  
Fusion Welding ◽  
Scientific Quality ◽  
Weld Quality ◽  
Ultrasonic Metal Welding ◽  
Quality Guidelines ◽  
State Process ◽  
Metal Welding ◽  
Welding Processes

Manufacturing of lithium-ion battery packs for electric or hybrid electric vehicles requires a significant amount of joining such as welding to meet desired power and capacity needs. However, conventional fusion welding processes such as resistance spot welding and laser welding face difficulties in joining multiple sheets of highly conductive, dissimilar materials with large weld areas. Ultrasonic metal welding overcomes these difficulties by using its inherent advantages derived from its solid-state process characteristics. Although ultrasonic metal welding is well-qualified for battery manufacturing, there is a lack of scientific quality guidelines for implementing ultrasonic welding in volume production. In order to establish such quality guidelines, this paper first identifies a number of critical weld attributes that determine the quality of welds by experimentally characterizing the weld formation over time. Samples of different weld quality were cross-sectioned and characterized with optical microscopy, scanning electronic microscopy (SEM), and hardness measurements in order to identify the relationship between physical weld attributes and weld performance. A novel microstructural classification method for the weld region of an ultrasonic metal weld is introduced to complete the weld quality characterization. The methodology provided in this paper links process parameters to weld performance through physical weld attributes.

scholarly journals Microstructural and spectrophotometric analysis system for metal welding processes

2019 ◽  
Author(s):  
Roberto Filippo ◽  
Pier Paolo Capra ◽  
Manuel Lai ◽  
Maria Giulia Faga
Keyword(s):  
Process Parameters ◽  
Production Systems ◽  
Microstructural Analysis ◽  
Welding Process ◽  
Spectrophotometric Analysis ◽  
Optical Systems ◽  
Source Power ◽  
Analysis System ◽  
Metal Welding ◽  
Welding Processes

We describe an analysis system for some of the most important methods of metal welding, based on the acquisition, study and comparison of the atomic emission spectra (in the range from 250 nm to 830 nm), hyperspectral imaging between 600 nm and 950 nm wavelengths and microstructural analysis. The radiometric measurement system acquires information while the welding process is in progress and acquired data are then compared with those resulting from the subsequent microstructural analysis. It is known that the process parameters like, for example, the source power or its speed over the parts during welding, significantly affect the mechanical properties and quality of the resulting junction like hardness, porosity, presence of cracks or other damages and so on. On the other hand, these properties and, above all, the changes in the joint features due to unwanted variations in the process parameters or in the materials being welded, can be inferred by studying the microstructure. In this sense, a proper correlation between the in situ spectral analysis and the microstructural properties is of paramount importance for controlling and adjusting the parameters during the process. In line with the requirements of Industry 4.0, the system described is a study of the application of metrology in a production line, designed to increase information about the production parameters of mechanical industry without increasing costs and limiting the complexity of additional installations. In this paper we report a series of experiments performed using LASER and TIG welding systems applied to different metals. The comparison between the welding conditions acquired by the optical systems and the methods of structural analysis are the basis of a project to improve production systems and their automation.

Investigation of the effects of welding variables on the welding defects of the friction stir welded high density polyethylene sheets

2021 ◽  
pp. 009524432110588
Author(s):  
Mustafa Kemal Bilici
Keyword(s):  
Friction Stir Welding ◽  
High Density Polyethylene ◽  
Welding Process ◽  
High Strength ◽  
High Density ◽  
Welding Parameters ◽  
Friction Stir ◽  
Wide Range ◽  
Welding Defects ◽  
Welding Processes

Modern thermoplastic materials are used in an expanding range of engineering applications, such as in the automotive industry, due to their enhanced stress-to-weight ratios, toughness, a very short time of solidification, and a low thermal conductivity. Recently, friction stir welding has started to be used in joining processes in these areas. There are many factors that affect weld performance and weld quality in friction stir welding (FSW). These factors must be compatible with each other. Due to the large number of welding variables in friction stir welding processes, it is very difficult to achieve high strength FSW joints, high welding performance, and control the welding process. Welding variables that form the basis of friction stir welding; machine parameters, tool variables, and material properties are divided into three main groups. Each welding variable has different effects on the weld joint. In this study, friction stir welds were made on high density polyethylene (HDPE) sheets with factors selected from machine parameters and welding tool variables. Although the welding performance, quality, and strength gave good results in some conditions, successful joints could not be realized in some conditions. In particular, welding defects occurring in the combination of HDPE material with FSW were investigated. Welding quality, defects, and performances were examined with macrostructure. In addition, the tensile strength values of some the joints were determined. The main purpose of this study is to determine the welding defects that occur at the joints. The causes of welding defects, prevention methods, and which weld variables caused were investigated. Welding parameters and welding defects caused by welding tools were examined in detail. In addition, the factors causing welding defects were changed in a wide range and the changes in the defects were observed.

Characterization of Ultrasonic Metal Welding by Correlating Online Sensor Signals With Weld Attributes

2014 ◽  
Author(s):  
S. Shawn Lee ◽  
Chenhui Shao ◽  
Tae Hyung Kim ◽  
S. Jack Hu ◽  
Elijah Kannatey-Asibu ◽  
...  
Keyword(s):  
Welding Process ◽  
Deep Understanding ◽  
Lithium Ion ◽  
Ultrasonic Welding ◽  
Diagnostic Methods ◽  
Quality Monitoring ◽  
Process Conditions ◽  
Ultrasonic Metal Welding ◽  
Bond Density ◽  
Metal Welding

Online process monitoring in ultrasonic welding of automotive lithium-ion batteries is essential for robust and reliable battery pack assembly. Effective quality monitoring algorithms have been developed to identify out of control parts by applying purely statistical classification methods. However, such methods do not provide the deep physical understanding of the manufacturing process that is necessary to provide diagnostic capability when the process is out of control. The purpose of this study is to determine the physical correlation between ultrasonic welding signal features and the ultrasonic welding process conditions and ultimately joint performance. A deep understanding in these relationships will enable a significant reduction in production launch time and cost, improve process design for ultrasonic welding, and reduce operational downtime through advanced diagnostic methods. In this study, the fundamental physics behind the ultrasonic welding process is investigated using two process signals, weld power and horn displacement. Several online features are identified by examining those signals and their variations under abnormal process conditions. The joint quality is predicted by correlating such online features to weld attributes such as bond density and post-weld thickness that directly impact the weld performance. This study provides a guideline for feature selection and advanced diagnostics to achieve a reliable online quality monitoring system in ultrasonic metal welding.

Characterization of Joint Quality in Ultrasonic Welding of Battery Tabs

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
S. Shawn Lee ◽  
Tae Hyung Kim ◽  
S. Jack Hu ◽  
Wayne W. Cai ◽  
Jeffrey A. Abell ◽  
...  
Keyword(s):  
Lithium Ion ◽  
Ultrasonic Welding ◽  
Fusion Welding ◽  
Scientific Quality ◽  
Weld Quality ◽  
Ultrasonic Metal Welding ◽  
Quality Guidelines ◽  
State Process ◽  
Metal Welding ◽  
Welding Processes

Manufacturing of lithium-ion battery packs for electric or hybrid electric vehicles requires a significant amount of joining, such as welding, to meet the desired power and capacity needs. However, conventional fusion welding processes, such as resistance spot welding and laser welding, face difficulties in joining multiple sheets of highly conductive, dissimilar materials to create large weld areas. Ultrasonic metal welding overcomes these difficulties by using its inherent advantages derived from its solid-state process characteristics. Although ultrasonic metal welding is well-qualified for battery manufacturing, there is a lack of scientific quality guidelines for implementing ultrasonic welding in volume production. In order to establish such quality guidelines, this paper first identifies a number of critical weld attributes that determine the quality of welds by experimentally characterizing the weld formation over time using copper-to-copper welding as an example. Samples of different weld quality were cross-sectioned and characterized with optical microscopy, scanning electronic microscopy (SEM), and hardness measurements in order to identify the relationship between physical weld attributes and weld performance. A novel microstructural classification method for the weld region of an ultrasonic metal weld is introduced to complete the weld quality characterization. The methodology provided in this paper links process parameters to weld performance through physical weld attributes.

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