Battery Cell Voltage Diagnosis Using Dual Moving Averages
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Solution Overview
Problem
Existing battery diagnostic methods struggle to accurately detect voltage abnormalities in battery cells due to variations in temperature, current, and State Of Health (SOH), leading to inefficiencies and prolonged processing times.
Innovation Solution
A battery diagnosing apparatus and method that determines short- and long-term movement averages of cell voltages, using a control circuit to analyze differences and deviations, and applies normalization and statistical variable thresholds to efficiently identify voltage abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple voltage detectors are connected in parallel to detect voltages of multiple battery cells, then voltage detection coverage is improved, but internal resistance of the detection system increases and detection precision deteriorates
Solution Approach 1:
The patent divides the battery pack into multiple groups based on battery cell strings, with each group having a dedicated detector. This segmentation allows comprehensive voltage monitoring without requiring all detectors to be connected in parallel to a single ADC, thereby maintaining detection precision while achieving wide coverage.
Solution Approach 2:
The patent introduces a hierarchical detection architecture where detectors are organized in groups corresponding to different battery cell strings. This dimensional organization transforms the flat parallel connection problem into a structured multi-level system, enabling independent ADC conversions for each group and eliminating the precision degradation caused by parallel connections.
2Reliability
If battery diagnosis is performed frequently to ensure safety and reliability, then diagnostic accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic diagnostic scheduling that adjusts the frequency and depth of diagnosis based on battery state and operational context. During normal operation, lightweight monitoring continues at low power, while comprehensive diagnosis is triggered only when necessary (e.g., abnormal conditions detected, charging/discharging cycles), thereby maintaining reliability while minimizing power consumption.
Solution Approach 2:
The patent employs progressive diagnosis strategies where not all battery parameters are always measured at full depth. Instead, essential parameters are continuously monitored at minimal power consumption, while complete diagnosis with all parameters is performed periodically or when triggered by specific conditions, achieving adequate reliability without excessive power usage.
Data Source
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AI summary
Disclosed is a battery diagnosing apparatus for a cell group, which includes a plurality of battery cells connected in series and is mounted in an electric vehicle, and the battery diagnosing apparatus includes a voltage sensing circuit configured to periodically generate a voltage signal representing a cell voltage of each battery cell while the electric vehicle is operating; and a control circuit configured to accumulatively store the cell voltage determined from the voltage signal in a memory unit and generate time series data representing the change over time in the cell voltage of each battery cell by using the accumulated cell voltage of each battery cell. The control circuit is configured to (i) determine a first average cell voltage and a second average cell voltage of each battery cell based on the time series data [where the first average cell voltage is a short-term movement average, and the second average cell voltage is a long-term movement average], and (ii) detect a voltage abnormality of each battery cell based on the difference between the first average cell voltage and the second average cell voltage.