Boosting battery quality control with automated SEM imaging

Battery quality control in battery manufacturing

In the competitive battery market, it’s more important than ever to optimize production costs. Staying competitive against new companies and joint ventures requires maximum profit per battery, and that means finding ways to streamline operations without negatively affecting quality and making confident, data-driven decisions.

This rapidly evolving landscape makes battery quality control a key consideration — it’s how you identify the line between a more cost-effective manufacturing process and one that turns out an inferior product. But how do you identify all the possible outcomes of a process change?
Scanning electron microscopes are powerful tools for this type of quality control, delivering visual feedback of minute variations in battery materials. However, accurately measuring features of interest in large volumes of SEM data can still be a challenge. That’s where automated image interpretation can help. Image interpretation software measures features of interest for you, removing operator bias and helping to ensure consistent, quality analysis.
Here are three use cases where automated image interpretation can deliver clear data.

Use case 1: optimizing the calendaring process

After the coating and drying steps of battery manufacturing, the calendaring process makes sure that the cathode material is properly packed and adheres to the aluminum tape, which enhances the battery’s energy density. If the mixture of particles and binder is poorly distributed on the cathode, you have an asymmetrical electrode. That reduces the number of cycles the battery can undergo.
To measure the accuracy of the particle distribution as well as the height of the sample, you first need a cross section of the cathode. This sample can then be refined with a broad ion beam polisher to remove damage from the cutting process and expose a surface that better represents the sample for SEM imaging. Finally, the imaging data is loaded into image segmentation software, which can automatically identify the cathode layer and measure its height.

Use case 2: validating packing density of active cathode materials

The sample preparation used in the first case study can also be used to validate packing density, which maximizes the amount of energy that the cell can hold, and examine cracks formed during calendaring that can impact cell lifetime.
While calendaring can help you reach your target packing factor by compressing particles closer together, it’s not enough to ensure consistency when working at the production scale. You must also monitor the particle size distribution, or granulometry, to make sure that there are enough particles of each size to fill the gaps between larger particles. Optical microscopy can validate this to a degree, but scanning electron microscopy can help you definitively detect the smallest particles.

Once the imaging data is collected, automated analysis not only identifies and measures all the particles in the image but also removes particles that touch an edge, identifies and distinguishes particles that are touching each other, and removes particles that are obstructed or overlapped by other particles. It then generates a particle size distribution diagram that provides an accurate description of the sample’s granulometry.

Use case 3: optimizing the curing process

A particle size distribution histogram can also be used to compare the primary particle structure of the precursor material with that of the finished cathode material. This analysis can help you optimize the time and temperature of the curing process, which can deliver significant cost savings.

In all of these use cases, automated image interpretation delivers accurate, unbiased data that can help you ensure that your samples comply with process requirements — and it saves valuable time during the manufacturing process.

Avizo Trueput Software for Battery Quality

The comprehensive suite of battery inspection workflows in Thermo Scientific Avizo Trueput Software for Battery Quality can help you ensure objective results and minimize operator bias. From processing data to generating detailed pass/fail reports, its standardized approach makes it easy for all users to feel confident in their work and make decisions firmly based in accurate data.
Within the expanding catalog of automated inspections, you’ll find a wealth of quality analysis tests that provide valuable insights into widely adopted protocols in your industry. Each test is seamlessly integrated into the software, so it easier for you to make it part of your standard operating procedure and scale up as needed.

Learn more about Avizo Treput Software