Over six and a half million electric vehicles were sold in 2021, that’s 108% more than were sold in 2020. The increase in demand has already permanently transformed the car manufacturing landscape, with almost all major automotive companies now operating electric vehicle production lines. While electric vehicles do have less moving parts than their internal combustion engine (ICE) counterparts, manufacturing them is still extremely complex. From stators and rotors, to intricate wiring harnesses, LMI is involved with many EV manufacturing applications. But the heart of an EV is its battery, and this is where machine vision solutions have become essential to market success.
EV Battery Manufacturing Overview
EV battery manufacturing can be broken up into 5 general steps: (1) electrode manufacturing, (2) cell assembly and packaging, (3) cell-to-module assembly, (4) module-to-pack assembly, and (5) final installation inspection. Gocator 3D smart sensors and they’re built in, onboard measurement tools are used in every stage of this manufacturing process. Let’s look at these applications individually.
During this step, Gocator sensors are used to ensure uniform shape and thickness of the electrode as the slurry is applied. Sensors are also used to measure the distance between tabs on a cell sheet. Tolerances are extremely small for these applications so high resolution and small field of view sensors are used.
Cell Assembly and Packaging
Two of the most common cell types used in electric vehicles are cylindrical and prismatic. Cylindrical cells are packed together into groups and scanned for presence/absence, correct position and dimensions, as as well as for potential surface defects such as any dents or scratches on the cell top.
Prior to welding, a Gocator® or multisensor network delivers high-speed 3D laser profiling and a built-in tool to measure the gap & flush between the prismatic batteries cell and its metal casing. After welding, they are inspected again to ensure that the weld. seam is uniform and within tolerances.
The surface of the battery cell needs to be inspected for correct dimensions and to detect defects of the face, edges, and corners.
Once the individual battery cells are inspected for quality control, a set number of them are precisely grouped together to form a battery module. An example application for module inspection is for sensors to measure and inspect the weld seams of each module.
Gocator sensors are used at the final stage of the process, combining modules into a single battery pack, ready to be installed into a new electric vehicle. It is necessary to measure and inspect its length, width, height, and flatness of each surface to ensure that all dimensions are matching the GD&T design tolerances.
Final Installation Inspection
In electric vehicles, a large tray/pan sits underneath the floor panel. The lithium-ion battery pack is glued to this tray. Gocator sensors are used at this final stage to inspect the glue bead application for correct dimensions (height, volume, width, length) and surface quality (breaks, gaps, overflow etc.).
EV battery production continues to grow rapidly around the world. LMI is not only supporting the current industry, but actively developing next generation sensors specifically designed to meet future battery production needs.