This solution is a battery monitoring unit CMU in the energy storage high-voltage battery management system based on NXP S32K118 and MC33774. The single board can monitor up to 54 battery strings and 12 temperature data. It adopts CAN-BUS architecture, and S32K118 and MC33774 use isolated SPI for communication. The main control uses NXP FS32K118LAT0MLFT, which is a Cortex M0+ core with a main frequency of 48MHz, 25KB SRAM and 256KB Flash; MC33774 is a battery monitoring and protection chip, the specific model is MC33774ASP1AE, which supports monitoring 4~18 battery strings, the maximum supply voltage can reach 90V, and the battery voltage and temperature are monitored through ADC, with a measurement range of -3V~5V. Under the conditions of -40℃~125℃, the maximum supporting balancing current is 360mA, and the average balancing current is 180mA; under the conditions of -40℃~150℃, the maximum supporting balancing current is 300mA, and the average balancing current is 150mA.

▶Scenario application diagram

▶Display board photo

▶Solution block diagram

Core technology advantages

①Support CAN-BUS architecture, CAN FD rate is up to 5Mbit/s.

② The cell voltage detection accuracy can reach ±0.8mV, and considering the PCB difference, the error can be within the range of ±2mV.

③ The deep sleep power consumption of a single MC33774 is as low as 15uA.

④ It has an I2C master device interface and can control slave devices such as off-chip EEPROM.

Solution Specifications

① Use external 24V power supply.

② Support communication with the master control via CAN.

③ Support monitoring of up to 54 battery strings.

④ Support single cell overvoltage and undervoltage detection, and the threshold can be set (Default: overvoltage 4.25V, undervoltage 2.75V).

⑤ Support 4-way battery high and low temperature detection, and the threshold can be set (Default: high temperature 70℃, low temperature -20℃).

⑥ The battery voltage sampling period is within 50ms, and the temperature sampling period is within 500ms.

⑦ Support disconnection detection.

⑧ Supports isolated SPI communication between MCU and AFE.

⑨ Supports a maximum balancing current of 300mA and an average balancing current of 150mA.

⑩ Each MC33774 corresponds to an off-chip EEPROM, which can support 512Kb data storage.