Vehicle Battery Cell Diagnosis via Time Constant Analysis
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Solution Overview
Problem
Existing battery management systems fail to accurately identify abnormal battery cells, leading to performance degradation and safety issues due to imbalances, overheating, or over-discharge, as they rely on simple parameters like current, voltage, or temperature.
Innovation Solution
A vehicle control device that monitors battery cells in a no-load state using time constants to diagnose their states by identifying first time constants, obtaining comparison datasets, and diagnosing abnormal states based on deviations from an average value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple battery management system based on current, voltage, or temperature parameters is used, then the system complexity is reduced, but the ability to accurately identify abnormal battery cells deteriorates
Solution Approach 1:
The patent changes the monitoring parameter from simple voltage to time constant characteristics. By measuring the time constant (τ = R × C) during no-load recovery, the system captures dynamic electrical behavior that reveals internal battery abnormalities, achieving higher diagnostic precision without proportionally increasing system complexity
Solution Approach 2:
The patent introduces time constant characteristics as an intermediary parameter that mediates between simple voltage measurement and complex battery state diagnosis. The time constant serves as a derived metric that translates basic electrical measurements into meaningful diagnostic information about battery health and abnormalities
2Measurement precision
If time constant-based diagnosis is implemented, then abnormal battery cell identification accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent creates a no-load condition before diagnosis by turning off the vehicle power supply. This preliminary action prepares the battery in a standardized state, allowing time constant measurements to be taken under consistent conditions, which simplifies the diagnostic process and improves accuracy without requiring complex real-time monitoring during operation
Solution Approach 2:
The patent implements periodic monitoring of time constant characteristics during no-load periods. By repeatedly measuring time constants at scheduled intervals, the system builds a historical dataset that enables trend analysis and more reliable abnormal cell identification, achieving high precision through systematic repeated measurements rather than complex continuous monitoring
3Measurement precision
If battery cells are monitored during no-load state, then diagnostic accuracy is improved, but the productivity is reduced due to additional time requirements
Solution Approach 1:
The patent performs time constant measurements during periodic no-load intervals when the vehicle is naturally idle. By utilizing these existing idle periods for diagnostic measurements, the system achieves high diagnostic accuracy without requiring dedicated measurement time that would reduce vehicle productivity, as the measurements occur during naturally occurring no-load states
Data Source
AI summary
A vehicle control device and a method thereof are provided. The vehicle control device includes a plurality of battery cells, a processor, and a memory. The processor is configured to identify first time constants of each of the battery cells, when a vehicle maintains a no-load state during a specified time, obtains a comparison dataset indicating a difference between an average value for the first time constants and each of the first time constants, and diagnoses a state of each of the battery cells, using the comparison dataset.