Battery Cell Under-Voltage Diagnosis Using Balancing Time
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery management systems face challenges in detecting under-voltage battery cells due to self-discharge events, making it difficult to diagnose abnormal cells during production and usage, which can lead to instability and reliability issues in electric vehicle batteries.
Innovation Solution
A battery management apparatus that calculates cumulative balancing time for each battery cell, compares it to reference times to determine abnormality, and diagnoses under-voltage cells by listing cells based on balancing time and standard deviation, allowing for early detection and stabilization of battery energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional voltage measurement methods are used to detect under-voltage battery cells, then the measurement process is simple, but the detection precision is insufficient because self-discharge events mask the voltage changes
Solution Approach 1:
The battery management apparatus performs preliminary balancing operations on battery cells before voltage measurement. By pre-charging or pre-discharging cells to a standardized state, the system eliminates the masking effect of self-discharge events, enabling accurate detection of true voltage levels without requiring complex measurement equipment
Solution Approach 2:
The system introduces balancing time and capacity deviation as intermediary parameters between the battery cell and the measurement process. These intermediaries provide indirect information about the cell's true state, allowing the system to detect under-voltage conditions even when direct voltage measurement is obscured by self-discharge events
2Reliability
If battery cells are monitored continuously to detect under-voltage conditions, then detection reliability improves, but the loss of time for data processing and analysis increases
Solution Approach 1:
The system performs preliminary sorting of battery cells based on capacity deviation before detailed under-voltage detection. This preliminary classification identifies which cells are most likely to be under-voltage, allowing the system to focus diagnostic resources on high-risk cells and reduce overall diagnosis time while maintaining high detection reliability
Solution Approach 2:
The detection process is segmented into multiple stages: initial capacity deviation calculation, preliminary cell sorting, targeted balancing operations, and final voltage verification. This segmentation divides the complex detection task into manageable steps, reducing processing time at each stage while maintaining overall detection reliability
3Measurement precision
If all battery cells undergo detailed balancing operations to ensure accurate detection, then detection accuracy improves, but the energy consumption and operation time increase
Solution Approach 1:
The system applies balancing operations selectively rather than uniformly to all battery cells. Based on capacity deviation thresholds and sorting results, only specific cells requiring balancing receive the operation, while cells already within acceptable ranges are excluded. This partial action maintains detection accuracy for problematic cells while minimizing unnecessary energy consumption on normal cells
Data Source
AI summary
Aspects of the disclosed technology include techniques, mechanism, and a battery management apparatus for diagnosing battery cells that may experience under-voltage. The battery management apparatus may determine a cumulative balancing time of each battery cell of a plurality of battery cells included in a battery pack. The battery management system may determine whether the battery pack is abnormal by comparing a median of the cumulative balancing times of each of the plurality of battery cells with a first reference time. The battery management apparatus may identify at least one under-voltage battery cell of the plurality of battery cells by comparing the cumulative balancing time of each of the plurality of battery cells with a second reference time when the median exceeds the first reference time.