BATman is a low power Battery Managment System, which calculates important battery values like state of health, state of charge and state of function. BATman provides the user the opportunity of monitoring the state of the cars battery during the runtime. The measurement parameters voltage and current for calculation are detected by an AS8510 measurement device, which communicates with an Atmel AT32UC3C microcontroller unit (MCU) via SPI. It gets the data with a frequency of 8 kHz for each value. To determine the values a shunt resistor is connected to the battery. The third parameter is the temperature, which is measured with an internal analog digital converter of the MCU. The ADC scales the voltage on a PT100 resistor. The MCU calculates the battery values after getting an interrupt from the measurement device. There are different ways of calculation for the different parameters. The SOC is determined with coulomb counting on one side and about the neutralvoltage on the other side. The SOH is calculated with the internal resistance of the battery. The values are stored in two different sorts of memories. The first memory is a SD-Card for storing data for the user in short time intervals. The second memory is an EEPROM. The EEPROM protects the software parameters in case of supply interruption. The microcontroller communicates with the SD-Card via SPI, too. The communication between EEPROM and controller comes about I2C. The user can access the battery data by connecting to BATman with Bluetooth. The user can set a real time clock which is supported by a 32 kHz oscillator. The Bluetooth IC works as data pump like a serial interface and it is connected with SPI to the microcontroller. For communication with other devices in automotive surrounding BATman includes a CAN communication unit, and allows the integration of LIN as well. An implemented USB socket allows a simplified programing of the MCU with a computer.
Autor: Philip Dost
Co-Autoren: Carsten Bindig, Constantinos Sourkounis
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