Wiring Harness News Sep-Oct 2022 - Page 54


Process Stability in Welding of Battery Cells With Ultrasonics

functionality of the battery cells . If individual foil layers are not completely joined together or if there are tears in the foil , which are only a few microns thick , this can lead to rejects and then to the disposal of the entire cell .
The ultrasonic welding machines from Herrmann provide a stable process for these connections . The HiS VARIO B 20 kHz systems have been specially developed for welding battery applications with multilayer foils . They reduce production waste and production costs .
Special battery design as a challenge
The special feature of the battery cell developed by CUSTOMCELLS ® is the size of the tabs . They are significantly smaller than what is typically used in the industry . In order to ensure a reliable connection between the tab and the anode or cathode , the sonotrodes of the ultrasonic welding machines were adapted to the respective size .
Thanks to ongoing research and development work , Herrmann Ultraschall was able to draw on an existing , special sonotrode design right at the start of the project . This guaranteed a reliable welding process for the CUSTOMCELLS ® battery application . After a short time , the appropriate welding parameters were also evaluated in the ultrasonic laboratory . The changeover to Herrmann welding systems could be implemented with virtually no downtime for production .
To insure battery production with the lowest possible reject rates , the ultrasonic welding system must be precisely matched to the application .

Systems from Herrmann Ultraschalltechnik GmbH & Co . KG reduced the reject rate for CUSTOMCELLS ® during the production of a new battery application and thus increased efficiency for this manufacturer .

As one of the world ’ s leading developers of customer-specific lithium-ion battery cells , CUSTOMCELLS ® pursues the lowest possible reject rate in battery production with maximum process reliability . For the welding of its applications , the development and production company relies on ultrasonic technology in one of their production lines . The ultrasonic welding systems from Herrmann Ultraschall used there minimized the reject rate and optimized production efficiency .
Optimization of the reject rate
In the associated production line , CUSTOMCELLS ® performs the prewelding and main welding on pouch cells . The first step in the pre-welding process is to pre-weld the individual layers of copper foil for the anode and the individual layers of aluminum foil for the cathode . In a second step , the main welding , the so-called tabs are welded to the cathode and anode .
Both pre-welding and main welding require strong , material-to-material connections to ensure the
As a particularly material-friendly joining process , ultrasonics is perfectly suited to permanently join the thin foils of the cathode and anode to the tabs in a reproducible manner .
Because of the variable size of the tabs , specially adapted sonotrodes must be used for the main weld .
Automation planned Both Herrmann welding systems are permanently used for the welding of cell tabs at CUSTOMCELLS ® . Within the scope of series production , the ultrasonic welding systems will be integrated into the automated production line in a next step . Ongoing consulting as well as the development of suitable welding solutions by Herrmann Ultraschall enable a smooth process integration .
Only by using ultrasonic welding systems that meet the demand and requirements , can reject rates in battery production be kept permanently at a low level . Flexible service by the ultrasonic partner is important for the success of a welding project in order to be able to react immediately to changes in the production process if necessary . The interaction of suitable welding solutions and good service forms the basis for safe and efficient production of battery applications with ultrasonics .
Currently still used as a manual workstation , the ultrasonic welding systems are to be integrated into CUSTOMCELLS ’ automated production line in the next step .
About Herrmann
As a specialist in ultrasonic welding , Herrmann has aimed to excite its customers for more than 60 years . For this purpose , Herrmann Engineering was developed which includes a combination of services . It enables more than 600 employees in over 20 countries to sucessfully implement projects together with their customers . The company ’ s mission “ Bonding — more than materials ”, stands for a close and trusting relationship . As a result , more than 2,000 different applications in key industries such as automotive , medical , hygiene and packaging can be solved every year . Visit www . herrmannultraschall . com