Battery Pack Current Sensor Diagnosis via Shunt Temperature Comparison

The patent segments the current measurement function into multiple independent measurement paths. Instead of relying on a single shunt resistor, the system uses multiple shunt resistors (first shunt resistor in the first current path and second shunt resistor in the second current path) to measure current. This segmentation ensures that if one measurement path fails, the other can still provide measurement capability, thus improving system reliability while maintaining current measurement accuracy.

The patent changes the measurement parameter from electrical voltage (across the shunt resistor) to thermal parameters (temperature differences). By measuring temperature differences between shunt resistors and switches, and comparing these with reference temperature differences, the system can detect abnormalities in the current sensor. This parameter change provides an additional layer of fault detection capability that enhances reliability.

The patent makes the temperature sensors serve multiple functions. The first and second temperature sensors not only monitor the temperatures of the first and second switches for thermal management purposes but also serve as part of the current sensor diagnosis system. By comparing the temperature differences of switches with shunt resistors against reference values, the same temperature sensors contribute to fault detection, thereby improving reliability without proportionally increasing device complexity.

The patent introduces reference temperature difference values as an intermediary element that enables diagnosis without requiring direct comparison of absolute temperatures. The diagnosis unit compares measured temperature differences (between shunt resistors and switches) with pre-stored reference temperature differences. This intermediary approach simplifies the diagnosis logic and reduces the complexity of real-time calculations while maintaining effective fault detection capability.