Effects of Simulated Battery-Relevant Contaminants on the Electrical Conductivity of Silicone Oil Under Controlled Conditions

Silicone oil is a promising dielectric coolant for battery immersion cooling, yet the ability of commercially available conductivity sensors to detect battery-related contamination remains poorly quantified. In this study, simulated carbonaceous particles, electrolyte, and mixed solid–liquid contaminants were introduced into silicone oil under controlled conditions using a closed-loop circulation platform, and conductivity was monitored in real time. Pristine silicone oil exhibited a baseline conductivity near the instrumental detection limit (approximately 1.26 μS·cm−1). No measurable conductivity increase was observed for particle concentrations up to 10 g·L−1 or electrolyte additions up to 3.0 vol%. Only under an intentionally extreme condition involving 20 vol% electrolyte and vigorous mixing were transient conductivity spikes of 350–550 μS·cm−1 detected. Thus, within the application-relevant concentration range examined, conductivity monitoring showed limited sensitivity to progressive contamination. These findings concern the response of a commercial low-field conductivity sensor and do not constitute a complete assessment of leakage current, dielectric strength, or full thermal-runaway conditions.