Battery Charge Threshold Control for Cell Voltage Imbalance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Battery cells in a pack exhibit varying available voltage ranges for charging and discharging due to differences in chemical properties, leading to capacity degradation and uneven capacity distribution among cells despite cell balancing efforts.
Innovation Solution
A battery management apparatus with a processor that adjusts charging and discharging threshold voltages based on cell voltage differences and state of charge (SOC) to optimize charging and discharging processes, using adaptive threshold calculations to maximize usable capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If cell balancing is performed to match the voltage ranges of the battery cells, then the voltage ranges are aligned, but repeated charging and discharging lead to variations in capacity among the battery cells
Solution Approach 1:
The patent implements dynamic adjustment of charging and discharging threshold voltages based on real-time cell voltage differences and SOC states. Instead of using fixed threshold values, the system continuously adapts the thresholds to account for individual cell characteristics and their changes over time, thereby maintaining capacity consistency despite repeated charge-discharge cycles
Solution Approach 2:
The system employs feedback mechanisms by measuring cell voltages during charging and discharging, comparing them against reference values, and using the deviations to adjust subsequent charging/discharging operations. This closed-loop control ensures that cells with varying capacities are managed optimally, preventing capacity degradation and maintaining reliability
2Productivity
If continuous charging and discharging operations are performed, then the battery module provides continuous power, but capacity degradation occurs among the battery cells
Solution Approach 1:
The patent applies local quality by treating each battery cell individually with customized charging and discharging threshold voltages based on its specific voltage characteristics and SOC state. This cell-level customization allows the system to maintain optimal performance for each cell while operating continuously, preventing uniform degradation across all cells
Solution Approach 2:
The system dynamically changes the threshold voltage parameters for charging and discharging operations based on real-time cell states. By adjusting these parameters according to cell voltage differences and SOC levels, the system enables continuous operation while mitigating capacity degradation through adaptive parameter optimization
3Device complexity
If fixed charging and discharging threshold voltages are used, then the control logic is simple, but the available voltage range is not optimized for cells with varying characteristics
Solution Approach 1:
The patent transitions from static fixed threshold voltages to dynamic adaptive thresholds that automatically adjust based on cell voltage differences and SOC states. This dynamic approach maintains reasonable system complexity while significantly improving adaptability to individual cell characteristics and maximizing the available voltage range for each cell
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A battery management apparatus includes a measuring unit including at least one sensor, the measuring unit configured to measure a cell voltage of each of a plurality of battery cells in a battery module, and a processor configured to adjust a charging threshold voltage or a discharging threshold voltage based on a difference in cell voltage between the plurality of battery cells and a current state of charge (SOC) of the battery module if charging or discharging the battery module.