Fast temperature measurement for safe battery charging

Controlling the temperature during the charging process is an important parameter for the safety and service life of batteries and inverters in the field of e-mobility. The ideal temperature at which a battery should be charged is around 30°C. At temperatures below this, the battery loses its capacity, but excessively warm temperatures will shorten its service life. At the same time, the charging voltage must be adapted to the temperature of the battery cell: a cold battery requires a higher charging voltage than a warm one.

The pre-assembled NTC thermistors of the NTC_999 series from Angst+Pfister Sensors and Power (formerly Pewatron) enable precise control of the charging process. The NTC thermistors are also available in a redundant version. These are all based on Murata’s extremely small NXFT15 NiCu sensor heads, enabling a very compact design and thus a particularly fast thermal response. Due to their low mass, the thermal time constant of these sensors is less than three seconds and thus up to three times faster than with conventional NTCs. AEC-Q200 certification for the NXFT thermistors is available as an option.

The designs available ex stock include configurations with a brass casing or mounting eyelets, twisted and non-twisted, with and without shrink tubing (see images). However, the closest possible contact between the thermistor and the battery is an absolute prerequisite for the best possible function. Angst+Pfister therefore offers custom assembly and optimal adaptation to the respective installation conditions.

In addition, Angst+Pfister offers a comprehensive range of other state-of-the-art components for power electronics. The new BeFAST evaluation board also provides a ready-to-use development tool for determining the relevant circuit properties in interaction with all essential components such as SiC FET circuit breakers, DC-DC converters, isolators, etc.

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