A High-Precision Temperature Control System for Electrochemical Measurements of Lithium-Ion Batteries and Individual Components

Temperature is critically important for lithium-ion batteries (LIBs) because it significantly impacts their performance, lifetime, and safety. Thermal control plays an important role in the reliability and safety of LIBs, since extreme temperatures can drastically reduce battery capacity and efficiency, implying irreversible damage, such as side reactions, leakages, and explosions. Consequently, a thorough understanding of the electrochemical behavior of the battery and individual components as a function of temperature is crucial for application. In this work, a temperature control system was designed using Swagelok-type cells and a silicone rubber heater, enabling a systematic electrochemical characterization across a wide temperature range up to 250 °C with high precision. Quantitative validation of the proposed system demonstrates significantly improved thermal stability compared to a conventional box furnace due to the localized heating configuration. At set temperatures of 40 and 70 °C, the developed system maintained stable profiles of 42 ± 0.4 and 71.5 ± 0.6 °C, respectively. To demonstrate its applicability, NMC811 half-cells were evaluated at 25 and 45 °C. Furthermore, the ionic conductivity of thin flexible polymer and dense ceramic solid electrolytes was determined within temperature ranges of 25–70 °C and 25–250 °C using electrochemical impedance spectroscopy to demonstrate the versatility of the temperature control system on evaluation of both battery cells and individual components. The results confirm that the proposed setup enables reliable electrochemical characterization with high temperature stability.