Current Sensor Abnormality Detection Using Battery Voltage Differences
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Solution Overview
Problem
Existing methods for determining abnormality in current sensors that detect battery current face challenges in accuracy, particularly when the current change is small, making it difficult to distinguish between sensor abnormalities and the small current consumption by in-vehicle devices.
Innovation Solution
A sensor abnormality determination device that acquires closed and open circuit voltages using a SOC-OCV characteristic curve, derives voltage differences, and determines abnormality based on these differences, improving accuracy by considering internal resistance and current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the deviation between voltage change and current change is used to determine sensor abnormality, then the method is simple to implement, but the accuracy of determining current sensor abnormality is low when current change is small
Solution Approach 1:
The patent introduces an intermediary parameter (voltage change derived from SOC-OCV characteristic curve) to mediate between the current sensor output and the actual battery state. By comparing the voltage change calculated from the characteristic curve with the voltage change derived from current sensor data, the system can accurately detect sensor abnormalities even when current change is small, thus resolving the contradiction between implementation simplicity and measurement accuracy.
2Ease of manufacture
If the deviation between voltage change and current change is used to determine sensor abnormality, then the implementation is straightforward, but it cannot distinguish between sensor abnormality and small current consumption by specific devices
Solution Approach 1:
The patent segments the voltage change analysis into two distinct components: (1) voltage change derived from the SOC-OCV characteristic curve which represents the battery's intrinsic voltage response, and (2) voltage change derived from current sensor data which includes both battery response and sensor measurement. By comparing these segmented components, the system can identify whether deviations are caused by sensor abnormalities or by legitimate small current consumptions, thus preventing false positives while maintaining implementation simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the accuracy of determining current sensor abnormalities by differentiating between voltage and current-induced voltage changes, effectively addressing the ambiguity in small current scenarios.
Implementation Method 1
a battery 30; a current sensor that detects a current of the battery
Implementation Method 2
a predetermined state of charge (SOC)-open circuit voltage (OCV) characteristic curve indicating a relationship between the state of charge and the open circuit voltage of the battery
Data Source
AI summary
A sensor abnormality determination device that determines abnormality in a current sensor includes an acquisition unit configured to acquire a closed circuit voltage of the battery and acquires an open circuit voltage of the battery obtained from a state of charge of the battery when the closed circuit voltage is acquired based on a predetermined SOC−OCV characteristic curve, a derivation unit configured to derive a first voltage difference which is a difference value between the closed circuit voltage and the open circuit voltage and a second voltage difference which is a change amount of a voltage obtained from a current of the battery detected by the current sensor and an internal resistance, and a determination unit configured to determine whether the current sensor is abnormal based on the first and the second voltage difference when the first voltage difference is equal to or larger than a first predetermined value.