Laser beam welding of electrical interconnections for lithium-ion batteries

Gedicke, Jens; Mehlmann, Benjamin; Olowinsky, Alexander; Gillner, Arnold

doi:10.2351/1.5062125

Cited by 6 publications

(1 citation statement)

References 2 publications

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“…Laser beam micro welding offers a highly automatable, contactless joining method whereby copper bonds can be processed. Compared to conventional welding processes, the intensity of the energy input is increased by focusing the laser beam down to several 10 µm in diameter to precisely weld materials with high thermal conductivity [4]. To protect the sensitive joining partners, a defined weld geometry is crucial in order not to damage the cell and at the same time to guarantee a large cross-section for the electrical current flow [5].…”

Section: Introductionmentioning

confidence: 99%

High-Precision Adjustment of Welding Depth during Laser Micro Welding of Copper Using Superpositioned Spatial and Temporal Power Modulation

Hummel

Häusler

Gillner

2021

JMMP

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For joining metallic materials for battery applications such as copper and stainless steel, laser beam micro welding with beam sources in the near-infrared range has become established in recent years. In laser beam micro welding, spatial power modulation describes the superposition of the linear feed motion with an oscillating motion. This modulation method serves to widen the cross-section of the weld seam as well as to increase the process stability. Temporal power modulation refers to the controlled modulation of the laser power over time during the welding process. In this paper, the superposition of both temporal and spatial power modulation methods is presented, which enables a variable control of the weld penetration depth. Three weld geometries transverse to the feed direction are part of this investigation: the compensation of the weld penetration depth due to the asymmetric path movement during spatial power modulation only, a W-shaped weld profile, and a V-shaped. The weld geometries are investigated by the bed on plate weld tests with CuSn6. Furthermore, the use of combined power modulation for welding tests in butt joint configuration between CuSn6 and stainless steel 1.4301 with different material properties is investigated. The study shows the possibility of precise control of the welding depth by this methodology. Depending on the material combination, the desired regions with maximum and minimum welding depth can be achieved by the control of local and temporal power modulation on the material surface.

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Section: Introductionmentioning

confidence: 99%

High-Precision Adjustment of Welding Depth during Laser Micro Welding of Copper Using Superpositioned Spatial and Temporal Power Modulation

Hummel

Häusler

Gillner

2021

JMMP

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Tracking the contour

Franz

Singpiel

Trein

2011

Laser Technik Journal

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in recent years the use of modern solid-state lasers has brought about a distinct increase in operational speed in laser materials processing. Whether with scanners or fixed optics, high speeds -as far as possible in various axes at the same time -have almost become the norm. But although the movement of the optic is precisely calculated, the position of the processing point can deviate from the planned contour. help is at hand, thanks to a process monitoring system developed by Fraunhofer iLT which precisely tracks the relative movement of work piece and optic. it enables acceleration related deviations from the set contour and speed to be measured exactly and the numerical control system to be adjusted accordingly. The kinematics measurement can be adapted to most laser processes (e.g. welding, brazing, cutting, selective laser melting, etc.) as an optional metrology method. 1Different fields of application for this new measurement system are shown in this article which represent three levels of machine integration. the first application for contour tracking is the assistance during the machine setup. By measuring for example a robots trajectory, the machine setter is enabled to modify the nc-program in order to optimize the robots kinematic behavior. Secondly, the kinematics measurement can be applied to qualify the machine's movements. if the measurement system is integrated into processing heads like welding or brazing heads, it empowers manufacturers to measure the trajectory and detect deviations from the required accuracy. the measured machine state can be documented for quality management purposes. the third application field requires also an integration into existing processing heads but rather than for off-line measurement it is used to measure the trajectory during the process in real-time. With short latency times it may provide a control of the laser power depending on the actual velocity. that type of system would automatically adjust the energy supply per unit length.

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