REUTLINGEN, Germany—Manz AG has developed a new laser welding process for use in lithium-ion battery cell production applications. It claims that the technology has numerous advantages over traditional ultrasonic welding, such as fewer steps needed to attach tabs.

“Laser Tab Welding…improves the quality, safety and process stability of the battery cell itself, and thus significantly reduces the cost per battery cell,” claims Axel Bartmann, head of marketing and corporate communications at Manz. “The new laser technology is nearly wear-free, flexible and a cost-efficient alternative to conventional ultrasonic welding.”

According to Bartmann, ultrasonic welding is typically associated with a high mechanical load. “Among other things, conventional ultrasonic welding requires pre-welding,” he points out. “This process step becomes unnecessary with [our] innovative laser technology.

“This reduces the complexity of production and increases the quality and safety of the battery cell, as well as process stability, due to the reduced number of process steps,” explains Bartmann. “Research is currently being carried out [reduce additional process steps].

“Initially, the acquisition costs for laser technology are higher than for the tried and tested ultrasonic method,” says Bartmann. “However, operating costs are steadily falling. [Our] new process is almost maintenance-free, achieves a significantly higher throughput per minute and overall better system availability is guaranteed through fewer failures. Fewer machines or modules mean that less space is required, and thus, smaller factories.”

According to Bartmann, benefits of laser welding include “more power, due to higher energy density, and more safety of the battery modules due to optimized cell protection than with previous cells. When welding, metal foils and tabs fuse together completely and thus form a very strong, crack-free connection. The compact weld seam can fix up to 160 layers, with increased welding quality.

“It has an extremely low electrical resistance and is up to three to five times stronger than an ultrasonic weld,” claims Bartmann. “This simple and safe process is scalable to up to 200 tabs in one collector.

“In addition, laser welding results in less abrasion due to contactless processing, which means reduced mechanical stress on the electrodes,” says Bartmann. “The laser source itself has a very high mechanical strength and is therefore hardly prone to errors. The new laser tool is wear-free, does not require readjustment and only needs to be replaced approximately every 15 years.”