Infineon designs IC specifically for EVs and HEVs
A sensing and balancing IC for battery management systems (BMS) in electric vehicles (EVs) and hybrid EVs (HEVs) has been introduced by Infineon Technologies. The TLE9012AQU measures the voltage in up to 12 battery cells with an accuracy of ± 5.8mV over the entire temperature and voltage range as well as the operating life cycle. It supports up to five external temperature sensors, provides an integrated cell balancing function and uses an iso-UART interface for communication.
A BMS ensures that the capacity of a battery is optimally utilised to achieve the longest possible range in an electric car, and to ensure that the battery does not age prematurely. They also determine the battery’s state of charge and state of health in order to estimate the available range and remaining service life. The TLE9012AQU provides measurement data and, through cell balancing, ensures a balanced state of charge. This prevents the weakest cell from determining the total usable capacity of the battery.
To minimise the influence of interfering signals on the measurement results, the TLE9012AQU features a programmable noise filter. It performs the measurement in all cells simultaneously so that the results remain comparable even in the presence of temporary interference factors. A compensation algorithm with integrated stress sensor and extended temperature compensation provides long-term stability of the measurements.
There are 12 balancing switches, one per cell, for cell balancing. The switches are designed for currents up to 150mA. For higher balancing currents, the device also supports external switches. The cell balancing can be programmed to stop without a signal from the microcontroller after a defined time of up to 32 hours or when the cell has reached a defined voltage. This allows the microcontroller to switch to sleep mode to save energy.
One TLE9012AQU can be used per module and an iso-UART interface performs data exchange between modules and the microcontroller for voltage isolation. More than 20 serially connected devices and a ring topology can be supported. According to Infineon, this ensures that even if a single device fails, the communication chain is not broken and the rest of the system remains functional.
The TLE9012AQU and matching iso-UART transceiver component (TLE9015QU) will both be available in July 2020.