Electric vehicle (EV) batteries are crucial for powering electric motors, ­making their quality inspection vital to avoid safety risks like malfunctions and short circuits. A new solution for welding inspection of EV batteries has been developed, focusing on precise and reliable inspection of weld seams. This ensures the structural integrity, safety, and reliability of the batteries, which are essential for their performance and longevity.

Malfunctions, short circuits, chemical leaks: these are all serious safety risks that need to be avoided when it comes to electric vehicle batteries, or EV batteries for short. EV batteries are batteries that have been specially developed for storing energy in electric vehicles (EVs). These batteries are at the heart of electric vehicles, as they store the electrical energy needed to power the electric motor. This makes it all the more important to check the quality of these batteries, as these inspections not only minimize safety risks, but also increase the longevity and efficiency of the products. 
This is exactly where the northern German technology company AT – Automation Technology comes into play, which has been developing and producing high-quality 3D components for more than 25 years and belongs to the global players in innovative 3D sensor technology. Together with its sales partner Fainstec, AT has come up with an application solution for the integrator Global Engineering Solutions (GES) in Korea, which involves the welding inspection of EV batteries. GES, which specializes in manufacturing systems for the quality control of electronic and energy components, came into contact with Fainstec as part of a search for a suitable 3D sensor for this very welding inspection. Their requirement: the integration of a product with which the weld seams of EV batteries can not only be scanned and inspected reliably, but above all precisely.

The Welding Inspection Application for EV Batteries

The GES inspection system is primarily concerned with a so-called „can-cap“ welding inspection. In this process, the cap is welded to the can of the battery, which not only requires a great deal of precision, but also a high speed for quality control during the production process. The sensor required should be able to detect the smallest defects of just 0.4 mm in size in the weld seam at a speed of 100 mm/s and at the same time take into account convex and concave areas, punched holes and the shape of the weld seam. 
„The challenge was not only to provide a fast sensor, but also one that could react flexibly to different requirements such as shape and curvature and deliver reliable scanning results. Thanks to our many years of experience in the machine vision industry and the advantages of our C6 CS series, which impresses in particular with its excellent combination of precision and speed, we were able to offer GES an optimal solution,“ says Dr. Athinodoros Klipfel, Head of Sales at AT. 
The Korean integrator GES therefore uses two AT sensors of type C6-1280CS35-7 GigE (405 nm, class 3R) for can-cap welding inspection. These offer a high resolution in X (5 µm) and Z (0.2 µm) as well as a profiling speed of up to 140 kHz. Furthermore, the C6 1280 sensors with a laser line width of 19 µm ensure precise and fast data acquisition as well as easy integration into any system thanks to its standard GenICam interface.

The Reason for the Welding Inspection of EV Batteries

Welds play a crucial role in the production of these vehicle batteries in many ways, as they contribute significantly to the structural integrity, safety and reliability of the battery packs. The battery cells in an EV battery pack must be firmly and securely connected to each other to withstand vibrations, shocks and other mechanical stresses that occur during vehicle use. Welded seams therefore ensure that the cells are securely fastened in the housing and prevent them from coming loose or shifting. They also protect the battery from external influences such as moisture, dust and other contaminants, so that no corrosion or short circuits occur. Another aspect is the electrical connection of the individual cells in the EV batteries. The weld seams must also be robust and reliable at this point in order to ensure a stable power supply and prevent overheating or electrical failures. And finally, the consistency of the weld seams is of course also crucial in the mass production of EV batteries. Automated welding processes that are precisely monitored and tested help to minimize production errors and ensure the safety of the batteries. 
„We have been working with AT since 2017 and are particularly familiar with the quality of their 3D sensors and their good feel for our customers‘ requirements. The C6 compact sensors used at GES fulfill exactly the requirements that the customer placed on the sensor for their inspection system thanks to their high resolution and profile speed. We were able to score points directly with GES so that they didn‘t need much time to make their decision,“ reports Jason Chung, Marketing Assistant at Fainstec.

Application with a Future

Welding Inspection with the AT sensors is now a common procedure that GES successfully uses with numerous end customers who test EV batteries. Thanks to this application, both the product quality of the batteries and operational safety have been significantly improved in various production lines. This application is successfully used in Korea and shows how crucial advanced sensor technology is for the future of e-mobility.