Multipoint temperature measurement using serially connected resistor–capacitor parallel circuits by impedance spectroscopy

•A novel measurement using serially connected resistor–capacitor parallel circuits by impedance spectroscopy is proposed.•Temperature at multiple points can be obtained with fewer cables compared with conventional approaches such as thermocouples.•The accuracy of the proposed method from conventional RTD measurement is confirmed to be 0.7 K in the temperature tested. [Display omitted] In this work, we aim to develop a novel measurement methodology using serially connected resistor–capacitor (RC) parallel circuits by electrochemical impedance spectroscopy (EIS). The advantage of the proposed methodology is that temperature at multiple points can be determined in a single measurement with fewer connected cables and a flexible assembly compared with conventional approaches such as those using thermocouples or resistance temperature detectors (RTDs). In the proposed methodology, multiple RC parallel circuits are used, each of which connects an RTD to a capacitor in parallel. Four experiments are conducted, i.e., single, double, triple, and quadruple RC circuits, to verify the feasibility of the proposed methodology at temperatures of 290–360 K. With the proposed methodology, we can successfully determine multipoint temperature using the serially connected sensors in a single measurement. The accuracy of the proposed method estimated from conventional RTD measurement results is confirmed to be 0.7 K in the temperature range tested. The proposed method can be applied to profile the temperature of electrochemical devices that operate at relatively low temperatures, such as lithium-ion batteries.