Recent data shows that electric vehicle (EV) demand is not meeting predictions, with many consumers dissuaded from purchasing an EV due to worries over performance and safety. Advanced imaging techniques such as scanning electron microscopy (SEM) are an essential part of both the quality assurance process and advanced battery research. Here, Dr. Jan Kretschmer, Senior Sales Manager at EM expert Thermo Fisher Scientific explores the vital role that electron microscopy technology plays in boosting EV performance and alleviating consumer concerns.
Although data from the Society of Motor Manufacturers and Traders shows that EV demand grew during the summer of 2024, the group predicted that sales would grow more slowly than expected for the remainder of the year. A sales slump means manufacturers risk missing long-term Zero Emissions Vehicles (ZEV) targets, which require EVs to represent 80 per cent of their sales by 2030. While pricing is a prohibitive factor for many, media coverage of EV fires and safety issues may also be dampening demand.
Most BEVs use lithium-ion batteries, due to their superior energy and power density compared with other commercially available battery technology. McKinsey’s Battery 2030: Resilient, sustainable and circular report shows that global lithium-ion demand for EVs alone will reach around 4,300 Gigawatt hours (GWh) by the end of the decade.
While the batteries are safe during normal use, overcharged, short-circuited or damaged cells present a fire risk. Therefore, the ongoing challenge is developing batteries that are not only safer and longer lasting, but also more environmentally friendly and cost effective. This is where advanced imaging technologies play a crucial role in combatting these challenges during battery production, quality control and research.
Enhancing battery production and assurance
From the production of the cathode, anode and battery cell right through to the assembly of the battery module, contaminants are a cause for concern. These contaminants may lead to a wide range of issues, such as reducing materials usage efficiency, accelerating cell degradation and potentially causing internal shorts, which in turn can cause safety risks.
Since battery contaminants generally have a low concentration level, traditional imaging approaches to detecting electrode impurities that generate grayscale images are slow and tedious. Identifying regions of interest for contamination analysis is difficult, as grayscale backscattered electron images only provide a compositional contrast based on atomic number, which is often hard to identify in grayscale.
The combination of energy dispersive X-ray spectroscopy (EDS) and SEM allows engineers to more thoroughly probe the structural and elemental information of contaminants. Using an advanced imaging solution such as Thermo Fisher’s Axia ChemiSEM can speed up the process by integrating SEM with ‘live EDS’ for immediate characterisation of electrode impurities. As the X-ray detection is always on, X-rays are acquired and processed in the background during the acquisition of the grayscale image to obtain quantitative elemental information. This allows engineers to easily visualise contaminants and address any concerns that may lead to safety issues.
Another important consideration when constructing the battery is characterising the binder distribution within the electrode, as this impacts the electrode’s quality and performance. While EDS can confirm the binder composition, the location information will be missing. This information is essential, as binder migration can result in reduced electrode stability and potential short-circuiting issues, which may lead to decreased capacity and cycle life and compromised safety.
Thermo Scientific Apreo ChemiSEM combines SEM analysis with Trinity in-column detection system, a unique detector making it easier to determine the distinction between binder and conductive carbon using charge contrast of these materials. The Trinity Detection System is different from traditional SEM design in that it incorporates three detectors (two in-lens and one in-column) that allow for precise energy and angular collection of both secondary and backscattered electrons, which is not achievable with conventional Everhardt-Thornley detectors (ETD) and below-the-lens detectors . This system improves performance by simultaneously acquiring topographical, surface, and compositional information without the need for additional ETD or BSD detectors, delivering an ultimate resolution of 0.9 nanometres (nm) at 1 kV without additional beam deceleration.
Image of a sample that was transferred to the Apreo 2 SEM with the CleanConnect System
Imaging’s role in research
In addition to assuring quality during the production process, microscopy has a crucial role to play in EV battery research. Many energy storage devices are limited by the performance of their constituent materials, meaning that researchers must thoroughly understand the material’s chemical and physical properties in order to overcome these limitations.
For air- and moisture-sensitive materials, this challenge is even more pronounced as the sample integrity must be preserved to characterise the material in its native state. In the context of battery research, reactive elements such as lithium can experience degradation when exposed to the environment during analysis. Consequently, microscopy solutions with complicated sample transfer processes can increase the time it takes to image materials and make preservation more difficult. Using an inert gas sample transfer workflow that employs a sample transfer solution such as Thermo Fisher’s CleanConnect not only helps preserve sample integrity but also enables uncomplicated sample handling with easy integration into SEM solutions.
Inert gas sample workflows can be employed with Thermo Fisher’s SEM portfolio to perform microanalysis or microanalysis with polishing. In workflows where ion-milling and polishing is required, Thermo Fisher’s Red Dot award-winning CleanMill Broad Ion Beam (BIB) system can quickly prepare the sample for imaging thanks to its high-energy ion source.
In order to reduce global vehicle emissions, the automotive industry must first alleviate consumer concerns surrounding EVs. Advanced imaging technology will be indispensable to perform research and quality control procedures that result in improved EV safety, range and adoption.
To discover how Thermo Fisher’s imaging technology could support your battery research or manufacturing application, visit our website.
