Influence of the surface properties of the connector material on the reliable and reproducible contacting of battery cells with a laser beam welding process

A numerical model was developed for predicting the bead geometry and microstructure in Laser Beam Welding of 2 mm thickness Inconel 718 sheets. The experiments were carried out with a 1 kW maximum power fiber laser coupled with a galvanometric scanner. Wobble strategy was employed for sweeping 1 mm wide circular areas for creating the weld seams and a specific tooling was manufactured for supplying protective Argon gas during the welding process. The numerical model takes into account both the laser beam absorption and the melt-pool fluid movement along the bead section, resulting in a weld geometry that depends on the process input parameters, such as feed rate and laser power. The microstructure of the beads was also estimated based on the cooling rate of the material. Features as bead upper and bottom final shapes, weld penetration and dendritic arm spacing were numerically and experimentally analyzed and discussed. The results given by the numerical analysis agree with the tests, making the model a robust predictive tool.

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Hybrid laser-arc welding of laser- and plasma-cut 20-mm-thick structural steels

Welding in the World ◽

10.1007/s40194-022-01255-y ◽

2022 ◽

Author(s):

Ömer Üstündağ ◽

Nasim Bakir ◽

Sergej Gook ◽

Andrey Gumenyuk ◽

Michael Rethmeier

Keyword(s):

Laser Beam ◽

Arc Welding ◽

Laser Beam Welding ◽

Digital Camera ◽

Welding Process ◽

Beam Power ◽

Beam Diameter ◽

Hybrid Laser Arc Welding ◽

Single Pass ◽

New Findings

AbstractIt is already known that the laser beam welding (LBW) or hybrid laser-arc welding (HLAW) processes are sensitive to manufacturing tolerances such as gaps and misalignment of the edges, especially at welding of thick-walled steels due to its narrow beam diameter. Therefore, the joining parts preferably have to be milled. The study deals with the influence of the edge quality, the gap and the misalignment of edges on the weld seam quality of hybrid laser-arc welded 20-mm-thick structural steel plates which were prepared by laser and plasma cutting. Single-pass welds were conducted in butt joint configuration. An AC magnet was used as a contactless backing. It was positioned under the workpiece during the welding process to prevent sagging. The profile of the edges and the gap between the workpieces were measured before welding by a profile scanner or a digital camera, respectively. With a laser beam power of just 13.7 kW, the single-pass welds could be performed. A gap bridgeability up to 1 mm at laser-cut and 2 mm at plasma-cut samples could be reached respectively. Furthermore, a misalignment of the edges up to 2 mm could be welded in a single pass. The new findings may eliminate the need for cost and time-consuming preparation of the edges.

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Comparative Study on Pulsed Laser Welding Strategies for Contacting Lithium-Ion Batteries

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1140.312 ◽

2016 ◽

Vol 1140 ◽

pp. 312-319 ◽

Cited By ~ 3

Author(s):

Patrick Schmitz

Keyword(s):

Laser Beam ◽

Comparative Study ◽

Weld Seam ◽

Laser Beam Welding ◽

Pulsed Laser ◽

Pulsed Laser Beam Welding ◽

Joining Process ◽

Suitable Process ◽

Pulsed Laser Beam ◽

Battery Cells

The transition towards renewable energy implicates more decentralized and time-dependent ways of energy generation. In order to deal with the resulting fluctuation in energy supply, local storage systems are necessary. Larger systems may consist of thousands of battery cells. Therefore, the reliable interconnection between the individual battery cells is the basic prerequisite for the production of these systems. It has been demonstrated that laser beam welding is a suitable process for the contacting of batteries. However, due to the high requirements regarding the heat input and the reproducibility of the joining process, further investigations are necessary. Within this work, experiments on pulsed laser beam welding of nickel-plated DC04 steel were conducted. Four different pulsed welding strategies were analyzed in a preliminary study in order to develop a method for obtaining suitable process parameters while reducing the amount of free parameters. Subsequently, a comparative study between the rectangular pulse, the shaped pulse, the spike pulse and the sloping pulse was carried out. The weld seam properties as well as the electrical and the mechanical properties of the connection joints were evaluated. The results presented in this paper indicate a high eligibility of pulsed laser beam welding as a joining process for the connection of battery cells. For all analyzed pulsed welding strategies a homogeneous weld seam without full penetration was observed. Similar electrical resistances for all strategies were measured despite the comparatively small total joint area for the discretely pulsed weld seams.

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Constrained Response Surface Optimization for a Laser Beam Welding Process

Journal of Mathematics and Statistics ◽

10.3844/jmssp.2011.5.11 ◽

2011 ◽

Vol 7 (1) ◽

pp. 5-11 ◽

Cited By ~ 1

Author(s):

Luangpaiboon

Keyword(s):

Laser Beam ◽

Response Surface ◽

Laser Beam Welding ◽

Welding Process ◽

Response Surface Optimization ◽

Surface Optimization

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Assessment of the Effect of Laser Welding on the Properties and Structure of TMCP Steel Butt Joints

Materials ◽

10.3390/ma13061312 ◽

2020 ◽

Vol 13 (6) ◽

pp. 1312 ◽

Cited By ~ 1

Author(s):

Jacek Górka

Keyword(s):

Laser Beam ◽

Welded Joints ◽

Research Work ◽

Laser Beam Welding ◽

Welding Process ◽

Tensile Tests ◽

Carbon Equivalent ◽

Quality Level ◽

Butt Joints ◽

Plastic Properties

The research work and related tests aimed to identify the effect of filler metal-free laser beam welding on the structure and properties of butt joints made of steel 700MC subjected to the TMCP (thermo-mechanically controlled processed) process. The tests involved 10-mm thick welded joints and a welding linear energy of 4 kJ/mm and 5 kJ/mm. The inert gas shielded welding process was performed in the flat position (PA) and horizontal position (PC). Non-destructive testing enabled classification of the tested welded joints as representing the quality level B in accordance with the requirements set out in standard 13919-1. Destructive tests revealed that the tensile strength of the joints was 5% lower than S700MC steel. The results of tensile tests and changes in structure were referred to joints made using the MAG (Metal Active Gas) method. The tests of thin films performed using a high-resolution scanning transmission electron microscope revealed that, during laser beam welding, an increase in dilution was accompanied by an increase in the content of alloying microadditions titanium and niobium, particularly in the fusion area. A significant content of hardening phases in the welded joint during cooling led to significant precipitation hardening by fine-dispersive (Ti,Nb)(C,N) type precipitates being of several nanometres in size, which, in turn, resulted in the reduction of plastic properties. An increase in the concentration of elements responsible for steel hardening, i.e., Ti and Nb, also contributed to reducing the weld toughness below the acceptable value, which amounts to 25 J/cm2. In cases of S700MC, the analysis of the phase transformation of austenite exposed to welding thermal cycles and the value of carbon equivalent cannot be the only factors taken into consideration when assessing weldability.

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