Depending on the cell technology, up to 300 lithium-ion cells are interconnected in series. Overvoltage and undervoltage, communication faults or interrupted lines to individual cells indicate safety-critical conditions in the battery system. For this reason, the STW.csc records every cell voltage and warns against pending limit value violations early on. The STW.csc cell sensor circuit therefore provides high-precision voltage measurement paths, an over/undervoltage monitoring system and a cell temperature monitoring device. A forced shutdown is carried out in case of safety limit violations. Passive balancing with 160 mA is used as the standard for the balance of charges between the cells. This value can also be adapted on request.
The STW.csc (Cell Sensor Circuit) monitors the individual cells of the battery through the measurement of voltage, temperature and SOC. Every STW.csc is equipped with a passive discharge path in order to balance out the battery cell charges. The cell sensor circuit communicates with the superordinate BMS.