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Maximizing throughput and minimizing downtime in battery production with ultrasonics

November 12, 2019


United States

Energy storage is one of the hot-button topics worldwide. E-mobility, mega factories, and more common stationary applications are relying heavily on lithium-ion batteries, for decentralized energy storage – creating huge industry growth and demand. The requirements for battery products have thus become increasingly diverse and complex. Ultrasonic welding systems by Herrmann Ultrasonics help manufacturers meet the highest standards in weld quality and comply with today’s requirements for process monitoring, quality assurance, and data acquisition.

The design of the Herrmann Ultrasonics HiS welding system, is flexible and modular, allowing for easy and rapid integration into different types of production lines for applications such as:
• Pre-welding for LIB (lithium-ion batteries)
• Tab-tab welding for LIB
• Welding of battery management systems
• Soft case sealing for LIB

Highest weld quality
Herrmann Ultrasonics has been a specialist in ultrasonic welding for decades and they have introduced a new welding system, the HiS VARIO B developed specifically for battery applications. Quality is controlled through assessment of weld process parameters and process monitoring. Fully digital generators precisely regulate important quality parameters such as frequency and amplitude for repeatable weld results. The VARIO controller allows process visualization through weld graphing on the 12” touch screen controller. Furthermore, major product and process requirements include:

• Reliable functionality of components
• Statistical process monitoring
• Data acquisition
• Calibration of equipment
• Long term process stability
• Minimum rejects

Easy Integration
The HiS VARIO B is designed with the goal of reducing operational costs, while maximizing throughput and minimizing downtime. Manufacturers often struggle with sonotrode changeover; in particular, alignment after changeover. The innovative and unique (patent pending) sonotrode alignment system assures fast, easy and repeatable tooling setup. The HIS VARIO B modular system offers complete integration solutions for machine builders and original equipment manufacturers.
• Small Footprint
• Left or Right versions for optimized manufacturing process flow and space savings
• Reduced total cost of ownership
• Reproducible results across multiple production facilities worldwide
• Easy and fast tool change

Ultrasonic welding for anode and cathode: a typical lithium-ion battery (LIB) uses copper foil as the current collector, called anode, and aluminum as the opposite current collector, called cathode. In a first step, called pre-welding, 20 to 60 foils are ultrasonically welded together, which requires a high level of process reliability. Burrs or cracks must be avoided completely. As for the second step, the specifications for the tab-welding demand a strong electric contact and no particles on the sealing film of the tab. Lastly, ultrasonic welding offers an alternative to heat sealing, when it comes to flexible LIB soft cases. The risk of damaging the cells is minimized by shorter cycle times and the use of cold ultrasonic welding tools rather than hot sealing bars.
Ultrasonic welding works for many electrical connections in the automotive, consumer and electronics industries with advantages like:
■ High strength
■ Short welding times
■ Low energy consumption
■ No consumables