Lithium-ion battery production using new laser welding technology

Welding joints between unit cells are more economical and reliable than screw contacts or dual metal busbars. However, the aluminum-copper contact welding for the surge protection device has its technical difficulty, because the greater the difference between the two metals, the more easily the resulting welding seam cracks. Traditional laser welding often faces such difficulties.

Manz Group, a leader in high-tech mechanical engineering, looks to the future growth market: electronic components, electronic devices, solar energy and electricity storage. Manz's expertise is based on six core technologies: automation, metrology, electrode printing, laser processing, chemical wet processing, and vacuum coating. Today: Manz's new laser welding technology developed for the production of lithium-ion batteries fully demonstrates our laser expertise.

Welding joints between unit cells are more economical and reliable than screw contacts or dual metal busbars. However, the aluminum-copper contact welding for the surge protection device has its technical difficulty, because the greater the difference between the two metals, the more easily the resulting welding seam cracks. Traditional laser welding often faces such difficulties.

Manz has developed a new industrial welding process that uses high-frequency local-modulation laser welding (abbreviated to "wavelike" welding), in which the melting of the mixed metal can be almost completely suppressed at the laser welding overlap. With wave soldering, the depth and width of the solder joints are only in the micrometer range and do not interfere with each other. Manz developed an automatic calibration method for a two-axis laser scanner system that can operate continuously at wave frequencies up to 4 kHz and maintain a stable micron penetration depth while reducing material defects.

Wave soldering does not form a brittle intermetallic phase, and the resulting seams have very high durability. At a joint length of each millimeter, the cross-section of the contact can be limited to from several hundred micrometers to one millimeter square, even when the metal sheet is thin. The newly developed high-frequency modulation overlap welding method also reduces the beam source power output by 80%, which can significantly reduce the cost of laser system technology.