Parallel Battery Pack Current Sensor Diagnosis by Ratio Comparison
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Solution Overview
Problem
Existing battery systems face challenges in accurately diagnosing overcurrents due to inaccuracies in current sensors, which can lead to incorrect state of charge estimation and potential vehicle malfunction.
Innovation Solution
A battery apparatus with parallel-connected battery packs and current sensors that utilize a processing circuitry to diagnose sensor accuracy by comparing calculated and measured current ratios based on resistance or capacity, using error tolerance coefficients to determine sensor normalcy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current sensors are used to measure battery pack current, then overcurrent diagnosis capability is improved, but measurement accuracy deteriorates due to sensor errors
Solution Approach 1:
The system uses feedback by comparing the ratio of measured currents from multiple current sensors with the ratio of calculated currents based on known battery pack specifications (resistance or capacity). This closed-loop comparison enables continuous monitoring and diagnosis of current sensor accuracy, allowing the system to detect measurement errors and diagnose sensor faults without adding external calibration equipment.
2Reliability
If multiple current sensors are deployed in parallel battery packs, then diagnosis coverage is improved, but system complexity increases
Solution Approach 1:
The system implements self-service by using the existing parallel battery pack configuration and current sensors to diagnose sensor accuracy. The processing circuitry automatically calculates expected current ratios based on battery pack specifications and compares them with actual sensor measurements, enabling the system to self-diagnose without requiring additional diagnostic sensors or external calibration equipment.
Solution Approach 2:
The current sensors serve multiple functions: they measure current for normal battery management operations and simultaneously provide data for self-diagnosis of sensor accuracy. The processing circuitry uses the same current measurements for both operational control and diagnostic purposes, eliminating the need for separate diagnostic hardware.
3Device complexity
If current sensor accuracy is not monitored, then system simplicity is maintained, but harmful effects increase due to undetected measurement errors
Solution Approach 1:
The system performs preliminary diagnosis by continuously monitoring current sensor accuracy through ratio comparison before measurement errors can cause harmful effects. By calculating expected current ratios based on battery pack specifications and comparing them with actual sensor readings in real-time, the system detects sensor drift or faults early, preventing incorrect state of charge estimation and potential vehicle malfunctions.
Data Source
AI summary
A battery apparatus, including a plurality of battery packs including a first battery pack and a second battery pack connected in parallel, a plurality of current sensors including a first current sensor measuring a current of a first battery pack, a second current sensor measuring a current of the second battery pack, and a processing circuitry diagnosing the first current sensor and the second current sensor based on a first ratio between a current of the first battery pack and a current of the second battery pack that are calculated based on resistances or capacities of the plurality of battery packs, and a second ratio between the current of the first battery pack and the current of the second battery pack that are measured by the plurality of current sensors.