The Fraunhofer Institute of Laser Technology (ILT), based in Aachen, on the France-Germany border, has invented a process combining copper 3D printing technology with their laser-based tape-automated bonding (LaserTAB) application to micro-weld prismatic, round and pouch cells battery cells.
This automated process, which combines both 3D printing and robotics will be displayed at the Munich Productronica exhibition in November 2017.
Laser scanning and and robotic microcell production
The LBR light-weight robot was developed for Fraunhofer ILT by Kuka Roboter GmbH, based in Augsburg, Germany, and is described by the company as the first sensitive robot to be manufactured in series. Researchers at Fraunhofer ILT have mounted a spacer and a relay optic on the robot to allow it to measure distance between the parts.
As a result, welding points are always held at a constant distance from the robot’s lens. As soon as the spacer makes contact with the weld, it begins the welding process continuously, also sensing when the process is complete. This automated behaviour has led the robot to be labelled an “intelligent industrial work assistant” (IIWA).
This new process is more accurate, precise and efficient than previous techniques for micro-welding cells. This required a manual search for a focus position and setting up of a laser.
Printing copper connectors
Fraunhoffer IIT has also created its own 3D printed copper connectors for the process. These copper contact elements are the connection points between the battery unit and individual round cells.
The process of 3D printing copper using selective laser melting (SLM) with a specially adapted green laser was invented by the institute earlier this year. The longer wavelength of green lasers means that less power is required for melting, and the copper transfers less heat energy to electricity.