New tool detects defects during Li-ion battery manufacture

Purdue University researchers have developed a tool to detect flaws in lithium-ion batteries as they are being manufactured.

The system works by measuring and monitoring how heat travels through them. First, the copper side of the battery's electrode is heated with a flashing xenon bulb, before an infrared camera reads the heat signature on the black side and produces a thermal image. The technology takes less than a second to work and is able to pick up various flaws that could affect battery performance and reliability, including scratches, air bubbles, contaminants and differences in thickness. "We showed that we can sense these differences in thickness by looking at the differences in temperature," said lead researchers Professor Douglas Adams. "When there is a thickness difference of 4%, we saw a 4.8% rise in temperature from one part of the electrode to another. For 1%, the temperature was 9.2% higher, and for 17% it was 19.2% higher." Adams says the thermal imaging process is ideal for a manufacturing line because it is fast and accurate, and can detect flaws prior to the assembly of the anode and cathodes into a working battery. "For example, if I see a difference in temperature of more than 1°, I can flag that electrode right on the manufacturing floor," he commented. "The real benefit, we think, is not just finding flaws but also being able to fix them on the spot."