Why Introduce SWIR Sensors into Electric Vehicle Battery Production Monitoring and Quality Control Testing?

As the demand for electric vehicles rises, quality control testing for batteries is essential to ensure that battery packs meet the stringent safety, performance, and quality requirements required for the electric vehicle industry. Unfortunately, current leak detection methods can be slow and inaccurate. Even tiny leaks can impact the battery’s performance and warranty costs. Even worse, leaks can cause electrical system short-circuits, fires, and damage to battery components.

A battery can be non-destructive tested before it leaves the factory. Automated Xray inspection can reveal defects in cells before they leave the factory. This prevents defective cells from being built into battery modules. Cell structure also affects quality control methods. Rolled cells are easy to inspect in 2D. But stacked cells require 3D computer imaging. This makes it difficult to interpret a transmissive-X-ray image.

Engineers evaluate the battery’s health during manufacturing by measuring its charge and discharge. They also evaluate the condition of the battery’s busbar, which is a long conductor isolated from ground and is responsible for distributing current throughout the battery pack. The busbar’s condition is important because it is the metric that determines the weld resistance for batteries. If the weld has any small resistance, this can cause excessive heat and early failures. By measuring the resistance before a battery is operational, engineers can remove any defective modules in the shortest time possible.

It is crucial to determine a battery pack’s life expectancy by using SoC information. It is possible to reduce the usable life of a lithium-ion battery pack by charging it too often or discharging it too frequently. The battery management software (BMS) also uses this information to ensure that the cells operate within safe limits. The BMS must include a charge estimator in order to calculate SoC.

Unlike voltage and temperature, SoC is difficult to measure directly. It must be calculated using specific parameters.

Adapting SWIR into the Lithium-Ion Battery Testing Process

For adaptability to existing production systems, it is possible to use high resolution, large field-of-view and extended SWIR cameras to overcome critical inspection challenges in the lithium-ion industry. This allows lithium battery producers to meet ever-higher quality specifications and perform better.

SWIR Vision’s Acuros SWIR cameras, for example, can provide imaging through the Li:Ion 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 are adaptable as quality control features throughout production due to their ability to see through things and send back high-resolution imagery at a rapid rate. We expect SWIR cameras to be adopted quickly for battery testing.