Pulsed Laser Welding of Battery Tabs for Porosity and Detachment

The patent applies periodic pulsed laser welding instead of continuous welding. The laser operates in discrete pulses with specific duty cycles, allowing heat to be applied intermittently rather than continuously. This periodic action prevents excessive heat accumulation that causes porosity and thermal distortion, while maintaining adequate welding speed through optimized pulse frequency and duration parameters.

The weld seam is divided into multiple discrete weld segments rather than creating one continuous weld. Each pulse creates a separate weld segment, and the collection of segments forms the complete weld. This segmentation allows heat to be distributed along the weld path in controlled portions, preventing localized overheating and improving overall weld quality while maintaining productivity.

The pulsed laser delivers high peak power during each pulse to ensure strong welds, but the periodic nature of the pulses allows cooling intervals between pulses. This prevents excessive heat accumulation that would cause thermal distortion and detachment, while the high peak power during each pulse ensures adequate weld strength is achieved.

The patent optimizes multiple laser parameters including pulse duration, frequency, duty cycle, and peak power. By carefully balancing these parameters, the system achieves high weld strength through sufficient peak power while controlling thermal distortion through appropriate pulse timing and energy distribution. The parameters are adjusted based on material thickness and composition.

The pulsed laser welding process allows simultaneous welding of multiple foil layers by delivering controlled energy bursts. Each pulse penetrates through multiple layers uniformly, and the periodic nature ensures heat doesn't accumulate excessively in any single layer, maintaining consistent weld quality across all layers while welding them simultaneously for improved productivity.

The laser parameters are specifically optimized for multi-layer welding, adjusting pulse duration, power, and frequency to achieve uniform penetration through multiple foil current collector layers. This ensures consistent weld quality across all layers while maintaining the efficiency benefit of welding multiple layers simultaneously.