Why include SWIR Sensors in Electric Vehicle Battery Production Monitoring and Quality Control Testing?

Quality control testing of batteries is vital to ensure that they meet stringent safety, performance, quality, and quality standards. Unfortunately, leak detection techniques are slow and inaccurate. Even tiny leaks could reduce the battery’s lifespan, decrease performance, or increase warranty costs. Even worse, leaks can cause electrical system short-circuits, fires, and damage to battery components.

Any defects in batteries can be identified before they leave the manufacturing facility by non-destructive testing. Automated radiographic inspection (X-ray inspection) can be used to examine hidden inner structures and identify defects before the cells leave the factory. This prevents the manufacture of defective cells into battery modules. The cell structure can also impact quality control methods. Rolled cells can be examined in 2D. Stacked cells, however, require 3D computer tomography. This is more difficult than interpreting a transmissive radiograph image.

Engineers evaluate the battery's health during manufacturing by measuring its charge and discharge. Engineers also assess the condition of the battery's battery's busbar. This is a conductor that is long and isolated from the ground. It is responsible for discharging current throughout the battery pack. It is crucial to test the busbar because it determines the battery's weld impedance. The weld resistance should not be too high. This can lead to premature failures and excessive heat. By measuring the resistance before a battery is operational, engineers can remove any defective modules in the shortest time possible.

The SoC information, in addition to performing testing, is essential to estimate a battery's usable lifetime. Overcharging or discharging a battery pack can drastically reduce its usable life. The battery management system (BMS), which uses this information to keep the cells within safe operating limits, also uses this information. To calculate SoC, the BMS must also include an accurate charge estimator.

SoC can't be measured directly, unlike voltage and temperature. It must be calculated using proprietary parameters.

SWIR can be used to adapt the Lithium-Ion Battery Testing Process

To adapt existing production systems to test equipment, high resolution, wide-field-of-view and extended SWIR camera can be used. They will help overcome many important inspection challenges that lithium-ion producers face.

When using SWIR Vision's Acuros sensor it provides imaging through the LiIon separator using SWIR wavelengths. These cameras, or sensors, provide the required alignment accuracy for inter-layer electrodes which directly leads to greater energy storage capacity and longer batteries lifetimes.

These sensors can be used to control quality throughout the production process due to their ability see through objects. We expect SWIR cameras to be adopted quickly for battery testing.