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Researchers from Drexel University in Philadelphia (USA) have developed a process for diagnosing Li-ion batteries to identify possible defects and prevent their thermal acceleration.
Frequent fires caused by Li-ion batteries have drawn attention to the timely detection of defects that cause thermal acceleration and cannot be detected by the naked eye. Researchers from Drexel University have proposed using the method of ultrasonic diagnostics of electrochemical processes inside the battery and its mechanical functions.
«Although lithium-ion batteries have been studied for almost half a century and went on sale more than 30 years ago, we have only recently developed tools that allow us to look inside with high resolution. Ultrasound has only been adapted from other fields, such as geophysics and biomedical sciences, to battery diagnostics in the last decade. Since it is a completely new technology in the battery and electric vehicle industry, it is necessary to educate battery engineers on how it works and why it is useful», — explains principal investigator of the Battery Dynamics Laboratory at Drexel College of Engineering, Ph Wes Chang.
The researchers have demonstrated an inexpensive and affordable benchtop ultrasonic device that they believe can be used by battery specialists, in particular those working on the production of electric cars. According to Consumer Affairs, people use 3 to 4 battery-powered appliances every day, including smartphones, laptops, tablets, power tools, and electric vehicles. The race to produce batteries for all these devices often leads to the commercial production of low-quality cells.
«Although the vast majority of lithium-ion batteries today are high-performance and safe, with thousands of cells used in electric vehicles and millions of electric vehicles produced annually, defects are inevitable», — Wes Chang notes.
Current processes for monitoring the safety and quality of manufactured batteries are based primarily on visual inspection and performance testing of individual cells manufactured batteries can be x-rayed to obtain a high-resolution image of the interior, but this is slow and expensive.
Manufacturers have to follow appropriate inspection and testing protocols, but given the scale of production, even a minor design or manufacturing defect that is not detected in advance can lead to a large batch of defective batteries being released to the market. The method proposed by the researchers from Drexel University uses ultrasound, which is faster and cheaper than using X-rays.
The researchers used scanning ultrasound microscopy to send low-energy sound waves through the battery Without affecting internal processes or battery performance, the speed of the waves changes as they pass through the different materials inside. This allows researchers to conduct a quick and thorough inspection of the chemical changes inside the battery.
In this way, structural defects or damage that can lead to a short circuit can be detected, as well as — material deficiencies and imbalances that can affect performance. The new diagnostic method is very good at detecting gas, the presence of which indicates dry areas that can lead to the failure of individual elements.
The sensitivity of ultrasound also makes it possible to evaluate how new chemical cells in batteries fail in research and development laboratories. As part of the study, the researchers collaborated with SES AI, a partner startup that manufactures lithium-metal batteries In addition to describing the ultrasonic testing process, the team also developed open-source software to control the device and perform quick analysis of the data.
«Battery scientists want to create better batteries, not develop new tools. We provide a user interface that is easy to use, with regular software updates. This complements the existing toolkit that battery scientists have at their fingertips to measure and diagnose the performance of next-generation batteries», — Wes Chang emphasizes.
The study was published in the journal Electrochimica Acta
Source: TechXplore
