Vehicle Battery Cell Voltage Diagnosis for Fast Drop Failures
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Solution Overview
Problem
Current low voltage diagnosis technologies for vehicle batteries are inadequate in detecting low voltage conditions caused by excessive cell deterioration, leading to potential fires during vehicle operation.
Innovation Solution
An apparatus and method for diagnosing vehicle battery low voltage and disconnection, utilizing different reference times based on the speed of voltage drop, and performing diagnosis independently of disconnection diagnosis results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional low voltage diagnosis condition (voltage < 1.5V for 5 seconds) is used, then the diagnosis is simple and fast, but it fails to detect low voltage caused by excessive cell deterioration where voltage drops below 0.5V before 5 seconds
Solution Approach 1:
The patent segments the voltage diagnosis into two independent modules: low voltage diagnosis (1.5V threshold, 5 seconds) and disconnection diagnosis (0.5V threshold, 30 seconds). Each module operates with its own reference time and voltage threshold, allowing both diagnosis types to function independently without interfering with each other's reliability.
Solution Approach 2:
The patent dynamically adjusts the diagnosis entry conditions based on the voltage drop rate. When the voltage drops faster than expected (indicating possible disconnection), the system enters disconnection diagnosis mode with extended time (30 seconds). When voltage drops normally, it uses standard low voltage diagnosis (5 seconds), making the diagnostic process adaptive to different failure modes.
2Reliability
If the voltage sensing abnormality diagnosis condition is changed to detect fast voltage drops, then low voltage detection improves, but misdiagnosis and over-diagnosis occur
Solution Approach 1:
The patent separates low voltage diagnosis and disconnection diagnosis into distinct modules with different entry conditions. Low voltage diagnosis enters when voltage < 1.5V, while disconnection diagnosis enters when voltage < 0.5V. This segmentation prevents misdiagnosis by ensuring each module only activates under its specific conditions, avoiding false positives from the other diagnosis type.
Solution Approach 2:
The system uses feedback from the voltage drop rate to determine which diagnosis module to activate. When the voltage drops faster than the normal rate (indicating possible disconnection), the system activates disconnection diagnosis with the 30-second reference time. This feedback mechanism ensures accurate diagnosis by matching the diagnostic approach to the actual failure mode.
3Device complexity
If a single diagnosis logic is used for both low voltage and disconnection, then the system is simple, but it cannot distinguish between normal low voltage and voltage sensing abnormality
Solution Approach 1:
The patent divides the diagnosis system into two independent modules: low voltage diagnosis module and disconnection diagnosis module. Each module has its own entry conditions (1.5V vs 0.5V), reference times (5 seconds vs 30 seconds), and diagnostic logic. This segmentation allows the system to maintain simplicity while accurately differentiating between normal low voltage and voltage sensing abnormalities.
Solution Approach 2:
Each diagnosis module is optimized with local quality specific to its function. The low voltage diagnosis uses a 1.5V threshold and 5-second reference time appropriate for normal operation monitoring. The disconnection diagnosis uses a 0.5V threshold and 30-second reference time appropriate for detecting severe deterioration. This local optimization ensures each module performs its specific function reliably.
Data Source
AI summary
The disclosure relates to an apparatus for diagnosing a battery of a vehicle, the apparatus being capable of performing reliable diagnosis with respect to low voltage of a battery of a vehicle, a battery diagnostic method thereof, and a vehicle system including the same. The apparatus may include a voltage sensor measuring voltage of a plurality of battery cells in the battery, and a processor performing low voltage diagnosis with respect to the battery on the basis of the cell voltage measured by the voltage sensor. The processor may determine whether or not the cell voltage satisfies a preset diagnostic condition when the cell voltage satisfies a diagnosis start condition, and when the processor determines that the cell voltage satisfies the diagnostic condition, the processor may diagnose that the battery is at a low voltage state.