Exact knowledge of thermal behavior and temperature curves is particularly important for the further development of high-performance high-voltage battery systems. The acquisition of temperatures between cells and other vital points throughout the battery must be done safely to protect personal and equipment. Often this is done at several hundred points at the same time. CSM’s HV DTemp measurement system was developed for the accurate, digital and thus interference-free acquisition of up to 512 temperature measurement points via a single cable connection to the HV DTemp-P central unit, without the need for further modification of the battery housing. The complete system, which is HV-safe up to 1,000 V DC, offers a measurement accuracy ±0.1 °C to ±0.25 °C, allowing for exact tracking of temperature curves. The very small temperature sensors used can be applied precisely yet flexibly in a variety of methods including using an ultra-thin flexible circuit that can be customized for specific applications. The compact and robust design allows measurements to be taken at all levels (cell level, module level, battery level). The measurement system is suitable for use on test benches as well as installed in vehicles for road tests.