Ultrasonic Welding Simulations for Multiple Layers of Lithium-Ion Battery Tabs

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Dongkyun Lee ◽  
Elijah Kannatey-Asibu ◽  
Wayne Cai
Keyword(s):  
Lithium Ion Battery ◽  
Automotive Industry ◽  
Semiconductor Industry ◽  
Computational Cost ◽  
Welding Process ◽  
Dissimilar Materials ◽  
Lithium Ion ◽  
Ultrasonic Welding ◽  
Simulation Procedure ◽  
Thermal Phenomena

Ultrasonic welding is a solid-state bond created using ultrasonic energy. It has been used in the semiconductor industry for several decades, and more recently, in the automotive industry such as for lithium-ion battery welding. Although there existed numerical simulations for ultrasonic welding, the models were limited to two-layer and like materials stackups. In this study, finite element theories are introduced and simulation procedure is established for multiple sheets and dissimilar metal ultrasonic welding. The procedures require both abaqus/Standard and abaqus/Explicit to simulate the coupled mechanical-thermal phenomena over the entire weld duration with moderate computational cost. The procedure is verified and used to simulate selected specific cases involving multiple sheets and dissimilar materials, i.e., copper and aluminum. The simulation procedure demonstrates its capability to predict welding energy, distortion, and temperature distribution of the workpieces. Case studies of ultrasonic welding simulations for multiple layers of lithium-ion battery tabs are presented. The prediction leads to several innovative ultrasonic welding process designs for improved welding quality.

Ultrasonic Welding Simulations of Multiple, Thin and Dissimilar Metals for Battery Joining

2012 ◽  
Author(s):  
Dongkyun Lee ◽  
Elijah Kannatey-Asibu ◽  
Wayne Cai
Keyword(s):  
Automotive Industry ◽  
Semiconductor Industry ◽  
Computational Cost ◽  
Welding Process ◽  
Dissimilar Materials ◽  
Ultrasonic Welding ◽  
Welding Quality ◽  
Dissimilar Metal ◽  
Simulation Procedure ◽  
Finite Element Procedure

Ultrasonic welding is a solid-state bond created using ultrasonic energy. It has been used in the semiconductor industry for several decades, and more recently, in the automotive industry such as for battery welding. Even though there existed several numerical simulations on ultrasonic welding, the models were too simplistic, in both theory and welding configuration, to present the multiple sheet, dissimilar metal ultrasonic welding. In this study, theories and a finite element procedure for the ultrasonic welding process are developed. The procedure invokes both Abaqus/Standard and Abaqus/Explicit to simulate the mechanical-thermal coupled phenomena over the entire weld duration with moderate computational cost. The procedure is verified and used to simulate selected specific cases involving multiple sheets and dissimilar materials, i.e., copper and aluminum. The simulation procedure demonstrates its capability to predict welding energy and temperature distribution of the workpieces, towards the goal of improving welding quality.

Joining Technologies for Automotive Lithium-Ion Battery Manufacturing: A Review

2010 ◽  
Author(s):  
S. Shawn Lee ◽  
Tae H. Kim ◽  
S. Jack Hu ◽  
Wayne W. Cai ◽  
Jeffrey A. Abell
Keyword(s):  
Lithium Ion Battery ◽  
Electric Vehicles ◽  
Hybrid Electric Vehicles ◽  
Dissimilar Materials ◽  
Lithium Ion ◽  
Cell Types ◽  
Advantages And Disadvantages ◽  
Battery Packs ◽  
Hybrid Electric ◽  
Battery Cells

Automotive battery packs for electric vehicles (EV), hybrid electric vehicles (HEV), and plug-in hybrid electric vehicles (PHEV) typically consist of a large number of battery cells. These cells must be assembled together with robust mechanical and electrical joints. Joining of battery cells presents several challenges such as welding of highly conductive and dissimilar materials, multiple sheets joining, and varying material thickness combinations. In addition, different cell types and pack configurations have implications for battery joining methods. This paper provides a comprehensive review of joining technologies and processes for automotive lithium-ion battery manufacturing. It details the advantages and disadvantages of the joining technologies as related to battery manufacturing, including resistance welding, laser welding, ultrasonic welding and mechanical joining, and discusses corresponding manufacturing issues. Joining processes for electrode-to-tab, tab-to-tab (tab-to-bus bar), and module-to-module assembly are discussed with respect to cell types and pack configuration.

A Method to Study Fatigue Life of Ultrasonically Welded Lithium-Ion Battery Tab Joints Using Electrical Resistance

2014 ◽  
Author(s):  
Nanzhu Zhao ◽  
Wei Li ◽  
Wayne W. Cai ◽  
Jeffrey A. Abell
Keyword(s):  
Fatigue Life ◽  
Lithium Ion Battery ◽  
Fatigue Test ◽  
Electrical Resistance ◽  
Hybrid Electric Vehicle ◽  
Damage Mechanics ◽  
Welding Process ◽  
Lithium Ion ◽  
Damage Variable ◽  
Life Model

The fatigue life of ultrasonically welded lithium-ion battery tab joints is studied for electric and hybrid-electric vehicle applications. Similar to metallic materials, the electrical resistance of these ultrasonic welds strongly depends on their quality and the crack growth under fatigue loading. A fatigue life model is developed using the continuum damage mechanics formulation, where the damage variable is defined using the electrical resistance of ultrasonic welds. Fatigue tests under various loading conditions are conducted with aluminum-copper battery tab joints made under various ultrasonic welding conditions. It is shown that the electrical resistance of ultrasonic welds increases characteristically during the fatigue life test. There is a threshold for the damage variable, after which the ultrasound welds fail rapidly. Due to welding process variation, welds made under the same process settings may have different fatigue performance. This quality difference may be classified using two parameters estimated from the fatigue life model. By monitoring the electrical resistance, it is possible to predict the remaining life of ultrasonically welded battery tab joints using only a portion of the fatigue test data. The prediction is more reliable by incorporating data beyond the half-life of the joints during the fatigue test.

Analysis of Weld Formation in Multilayer Ultrasonic Metal Welding Using High-Speed Images

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
S. Shawn Lee ◽  
Tae Hyung Kim ◽  
S. Jack Hu ◽  
Wayne W. Cai ◽  
Jeffrey A. Abell
Keyword(s):  
High Speed ◽  
Lateral Displacement ◽  
Welding Process ◽  
Lithium Ion ◽  
Ultrasonic Welding ◽  
Fusion Welding ◽  
Tool Geometry ◽  
Weld Quality ◽  
Weld Formation ◽  
Welding Processes

One of the major challenges in manufacturing automotive lithium-ion batteries and battery packs is to achieve consistent weld quality in joining multiple layers of dissimilar materials. While most fusion welding processes face difficulties in such joining, ultrasonic welding stands out as the ideal method. However, inconsistency of weld quality still exists because of limited knowledge on the weld formation through the multiple interfaces. This study aims to establish real-time phenomenological observation on the multilayer ultrasonic welding process by analyzing the vibration behavior of metal layers. Such behavior is characterized by a direct measurement of the lateral displacement of each metal layer using high-speed images. Two different weld tools are used in order to investigate the effect of tool geometry on the weld formation mechanism and the overall joint quality. A series of microscopies and bond density measurements is carried out to validate the observations and hypotheses of those phenomena in multilayer ultrasonic welding. The results of this study enhance the understanding of the ultrasonic welding process of multiple metal sheets and provide insights for optimum tool design to improve the quality of multilayer joints.

New Joining Techniques for the Production of the Electrical Components in the Automotive Industry

2018 ◽  
Vol 1146 ◽  
pp. 98-105 ◽  
Author(s):  
Radu Cojocaru ◽  
Cristian Ciucă ◽  
Lia Nicoleta Boţilă ◽  
Victor Verbiţchi ◽  
Ion Aurel Perianu
Keyword(s):  
Friction Stir Welding ◽  
Production Process ◽  
Automotive Industry ◽  
Welding Process ◽  
Dissimilar Materials ◽  
Butt Welding ◽  
Friction Stir ◽  
Preliminary Results ◽  
Friction Stir Welding Process ◽  
Electrical Components

In the paper are presented some preliminary results regarding the possibilities of using of the friction stir welding process (FSW) and FSW assisted with TIG (FSW – TIG) welding for joining of the electrical components in the automotive industry. Couples of dissimilar materials approached in experiments were Aluminium EN AW 1200 and Copper Cu99, with thicknesses in conformity with real cases in the production process. The results obtained for butt welding an overlap welding of different thicknesses of materials (aluminium thickness s1 = 2mm and copper thickness s2 = 5mm) are presented. There are some general conclusions regarding the possibilities of joining the two materials under the specified conditions.

Application of Non-Linear Krylov Solvers for Conjugate Heat Transfer Simulations of Electrical Battery Packs

2021 ◽  
pp. 1-33
Author(s):  
Parvez Sukheswalla ◽  
Raju Mandhapati ◽  
Chu Wang ◽  
Nitesh Attal ◽  
Kislaya Srivastava
Keyword(s):  
Heat Transfer ◽  
Fixed Point ◽  
Lithium Ion Battery ◽  
Conjugate Heat Transfer ◽  
Energy Equation ◽  
Computational Cost ◽  
Lithium Ion ◽  
Battery Pack ◽  
Anisotropic Thermal Conductivity ◽  
Non Linear

Abstract Krylov-based methods are an attractive alternative to traditional fixed-point iterative schemes, being much more robust and accurate when solving elliptic equations (e.g., the energy equation in the solid domain). This study assesses the performance of a Krylov-based accelerator, when used for Conjugate Heat Transfer (CHT) simulations of an electrical battery-pack. The non-linear nature of CHT simulations (due to spatial & temporal changes in boundary conditions) necessitates the use of the non-linear form of the Krylov-based accelerator (termed NKA). NKA is used while performing steady-state CHT simulations of an air-cooled Lithium-ion battery-pack, specifically to help accelerate the solution of the solid-domain energy equation. The effect of using either isotropic or anisotropic thermal conductivity within the cylindrical Lithium-ion battery cells is also evaluated. Results obtained using the NKA accelerator are compared, in terms of accuracy and speed, to those obtained from a traditional non-linear fixed-point iterative scheme based on Successive Over-Relaxation (SOR). The NKA accelerator is found to perform quite well for the problem at hand, providing results with the specified accuracy, while also being between 5 and 20 times faster than SOR (while solving the solid energy equation). The robust nature of NKA also leads to better global heat-balance within the battery-pack at all times during the simulation. Overall, computational cost reductions of 30% to 40% are observed when using NKA for the battery-pack simulations.

scholarly journals An integrated online adaptive state of charge estimation approach of high-power lithium-ion battery packs

2017 ◽  
Vol 40 (6) ◽  
pp. 1892-1910 ◽  
Author(s):  
Shunli Wang ◽  
Carlos Fernandez ◽  
Liping Shang ◽  
Zhanfeng Li ◽  
Huifang Yuan
Keyword(s):  
Lithium Ion Battery ◽  
Real Time ◽  
High Power ◽  
Computational Cost ◽  
Estimation Method ◽  
Equivalent Circuit Model ◽  
Lithium Ion ◽  
State Of Charge ◽  
The Real ◽  
Soc Estimation

A novel online adaptive state of charge (SOC) estimation method is proposed, aiming to characterize the capacity state of all the connected cells in lithium-ion battery (LIB) packs. This method is realized using the extended Kalman filter (EKF) combined with Ampere-hour (Ah) integration and open circuit voltage (OCV) methods, in which the time-scale implementation is designed to reduce the computational cost and accommodate uncertain or time-varying parameters. The working principle of power LIBs and their basic characteristics are analysed by using the combined equivalent circuit model (ECM), which takes the discharging current rates and temperature as the core impacts, to realize the estimation. The original estimation value is initialized by using the Ah integral method, and then corrected by measuring the cell voltage to obtain the optimal estimation effect. Experiments under dynamic current conditions are performed to verify the accuracy and the real-time performance of this proposed method, the analysed result of which indicates that its good performance is in line with the estimation accuracy and real-time requirement of high-power LIB packs. The proposed multi-model SOC estimation method may be used in the real-time monitoring of the high-power LIB pack dynamic applications for working state measurement and control.

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.

Joint Formation in Multi-Layered Ultrasonic Welding of Ni-Coated Cu and the Effect of Preheating

2018 ◽  
Author(s):  
Ying Luo ◽  
S. Jack Hu ◽  
Elijah Kannatey-Asibu ◽  
Haseung Chung ◽  
Wayne Cai ◽  
...  
Keyword(s):  
Joint Strength ◽  
Early Stage ◽  
Welding Process ◽  
Lithium Ion ◽  
Ultrasonic Welding ◽  
Mechanical Interlocking ◽  
Joint Formation ◽  
Single Interface ◽  
Process Robustness ◽  
Cu Bonding

Multi-layered ultrasonic welding (USW) is widely used in joining of electrodes or tabs in lithium-ion batteries. To achieve quality joints and enhance the welding process robustness, an improved understanding of the joint formation is highly desirable. In this paper, USW of 4-layered Ni-coated Cu is studied to investigate the joint formation at a single interface and joint propagation from interface to interface under both ambient and preheated conditions. The results indicate that joint formation involves three major mechanisms: Ni-Ni bonding with minimal mechanical interlocking, Ni-Ni bonding with moderate mechanical interlocking, and a combination of Ni-Ni bonding, Cu-Cu bonding, and severe mechanical interlocking. Results also show that joints propagate from the interface close to the sonotrode side to that close to the anvil side. It is further observed that the joint formation can be accelerated and the joint strength can be improved with process preheating, especially at the interface closest to the anvil. The effect of preheating is most significant during the early stage of the process, and diminishes as process progresses. The favorable effects of preheating improve the robustness of multi-layered USW.

Joint Formation in Multilayered Ultrasonic Welding of Ni-Coated Cu and the Effect of Preheating

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Ying Luo ◽  
Haseung Chung ◽  
Wayne Cai ◽  
Teresa Rinker ◽  
S. Jack Hu ◽  
...  
Keyword(s):  
Joint Strength ◽  
Early Stage ◽  
Welding Process ◽  
Lithium Ion ◽  
Ultrasonic Welding ◽  
Mechanical Interlocking ◽  
Joint Formation ◽  
Single Interface ◽  
Process Robustness ◽  
Cu Bonding

Multilayered ultrasonic welding (USW) is widely used in joining of electrodes or tabs in lithium-ion batteries. To achieve quality joints and enhance the welding process robustness, an improved understanding of the joint formation is highly desirable. In this paper, USW of four-layered Ni-coated Cu is studied to investigate the joint formation at a single interface and joint propagation from interface to interface under both ambient and preheated conditions. The results indicate that joint formation involves three major mechanisms: Ni–Ni bonding with minimal mechanical interlocking, Ni–Ni bonding with moderate mechanical interlocking, and a combination of Ni–Ni bonding, Cu–Cu bonding, and severe mechanical interlocking. Results also show that joints propagate from the interface close to the sonotrode side to that close to the anvil side. It is further observed that the joint formation can be accelerated and the joint strength can be improved with process preheating, especially at the interface closest to the anvil. The effect of preheating is most significant during the early stage of the process, and diminishes as process progresses. The favorable effects of preheating improve the robustness of multilayered USW.

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