Diagnostic system for a battery system

A diagnostic system for a battery system, the battery system having a battery module electrically coupled to a contactor, the battery module having first, second, and third battery cells, comprising:

• a first microcontroller obtaining a first initialization value and first, second, and third battery cell comparator overvoltage flag values from a memory device, the first, second, and third battery cell comparator overvoltage flag values being associated with the first, second, and third battery cells, respectively;
• the first microcontroller further obtaining a second initialization value, a first battery module fault line voltage flag value, and a second battery module fault line voltage flag value from the memory device;
• the first and second battery module fault line values being associated with the battery module;
• the first microcontroller initializing each of first, second, and third battery cell comparator overvoltage flags to the first initialization value;
• the first microcontroller receiving first, second, and third comparator bits from a second microcontroller;
• the first comparator bit having a first fault value if a first output voltage of the first battery cell is greater than a first threshold voltage;
• the second comparator bit having the first fault value if a second output voltage of the second battery cell is greater than the first threshold voltage;
• the third comparator bit having the first fault value if a third output voltage of the third battery cell is greater than the first threshold voltage;
• the first microcontroller setting the first battery cell comparator overvoltage flag equal to the first battery cell comparator overvoltage flag value if the first comparator bit is equal to the first fault value;
• the first microcontroller setting the second battery cell comparator overvoltage flag equal to the second battery cell comparator overvoltage flag value if the second comparator bit is equal to the first fault value;
• the first microcontroller setting the third battery cell comparator overvoltage flag equal to the third battery cell comparator overvoltage flag value if the third comparator bit is equal to the first fault value;
• the first microcontroller transitioning the contactor to the open operational state if the first battery cell comparator overvoltage flag is equal to the first battery cell comparator overvoltage flag value or the second battery cell comparator overvoltage flag is equal to the second battery cell comparator overvoltage flag value or the third battery cell comparator overvoltage flag is equal to the third battery cell comparator overvoltage flag value;
• the first microcontroller initializing a battery module fault line voltage flag to the second initialization value;
• the first microcontroller measuring a battery module fault line voltage on a fault line coupled to and between the first and second microcontrollers, the first microcontroller generating a battery module fault line voltage value based on the battery module fault line voltage;
• the first microcontroller setting the battery module fault line voltage flag equal to the first battery module fault line voltage flag value if the battery module fault line voltage value is equal to a fault voltage value indicating an overvoltage condition in at least one of the first, second, and third battery cells in the battery module;
• and
• the first microcontroller transitioning the contactor to the open operational state if the battery module fault line voltage flag is equal to the first battery module fault line voltage flag value.