Active Balance Control for Lithium Iron Phosphate Battery Packs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing active balance control methods for battery packs are ineffective for lithium iron phosphate batteries with flat voltage curves, limiting their application range and leading to inconsistent battery performance and reduced service life due to temperature differences and aging issues.
Innovation Solution
A method for active balance control that calculates a reference balance current ratio and actual balance current ratio, using a tracking algorithm to adjust and maintain balance, allowing for real-time tracking and control across different battery pack states, including charging, working, and resting batches, and employing both BCR-based and voltage-based balance methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing active balance control method is used, then it is effective for ternary battery with steep voltage curve, but it has poor effect for lithium iron phosphate battery with flat voltage curve
Solution Approach 1:
The patent introduces dynamic batch identification and state classification mechanisms that adapt the balance control strategy based on real-time battery pack conditions. The system dynamically switches between different control methods (voltage-based or current ratio-based) depending on the detected batch state, making the control method effective across different battery chemistries and operating conditions.
Solution Approach 2:
The patent changes the control parameter from fixed voltage-threshold-based control to dynamic balance current ratio control. By calculating reference balance current ratios specific to each batch and using inter-batch iteration methods, the system adapts to different battery characteristics (steep or flat voltage curves) and maintains effective balance control across various battery types.
2Reliability
If temperature difference between battery cells increases during long-term use, then manufacturing limitations cause strong inconsistency, but active balancing can transfer energy to improve consistency
Solution Approach 1:
The patent implements continuous monitoring and feedback mechanisms by calculating actual balance current ratios in real-time and comparing them against reference values. The system uses feedback from batch state classification and inter-batch iteration to continuously adjust balance control strategies, ensuring consistent performance despite temperature variations and cell inconsistency.
Solution Approach 2:
The patent performs preliminary classification of batch states and calculates reference balance current ratios before executing balance control. By pre-identifying the operating batch type (charging, working, or resting) and determining appropriate reference parameters in advance, the system prepares optimal control strategies that prevent inconsistency from developing due to temperature differences.
3Duration of action of stationary object
If battery pack has poor consistency, then aging rate increases and service life decreases, but real-time tracking control can extend service life
Solution Approach 1:
The patent ensures continuous balance control by implementing real-time tracking algorithms that operate across all batch states (charging, working, resting). The inter-batch iteration method maintains continuous optimization of balance current ratios, ensuring uninterrupted balance action that prevents aging acceleration and extends service life through sustained consistency management.
Data Source
AI summary
A method, system and device for active balance control of a battery pack are disclosed. The method includes: calculating a reference balance current ratio of a battery cell to a battery pack in each batch; calculating an actual balance current ratio of the battery cell to the battery pack at each moment in any batch; allowing the actual balance current ratio to track the reference balance current ratio of the corresponding batch in real time by executing a preset tracking algorithm; and performing balance control on the battery pack according to a tracking result. The system includes a first calculation module, a second calculation module, a tracking module, and a balance control module. The device includes a memory and a processor.