Battery Cell Probability Control for State of Charge Balancing
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Solution Overview
Problem
Existing battery systems struggle to effectively balance the state of charge among battery cells, resulting in significant differences that are barely recognizable when state of charge variations are less than 5%, leading to inefficient battery cell utilization and drainage patterns.
Innovation Solution
A method where each battery cell is electrically coupled and decoupled based on calculated probabilities derived from a second quality factor, which is a linear function of the difference between its individual quality factor and an average quality factor, allowing for more precise control over activation and deactivation during charging and discharging processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If battery cells are connected in series with equal probability, then the control algorithm is simple, but the state of charge balancing between cells is ineffective when differences are less than 5%
Solution Approach 1:
The patent applies local quality by assigning different connection probabilities to different battery cells based on their individual states of charge. Instead of uniform treatment, each cell receives customized control parameters (P1, P2) calculated from its specific quality factor, enabling precise balancing of small state of charge differences while maintaining systematic control.
2Ease of operation
If all battery cells are treated equally, then the system operation is simple, but cells with different states of charge are not optimally utilized
Solution Approach 1:
The patent changes the operational parameters by dynamically adjusting connection probabilities P1 and P2 for each battery cell based on its state of charge and quality factor. This parameter adaptation allows the system to optimize cell utilization efficiency without requiring complex manual intervention, as the parameters are automatically recalculated and updated.
3Device complexity
If uniform connection probability is used for all battery cells, then the control mechanism is straightforward, but small state of charge differences remain unaddressed
Solution Approach 1:
The patent implements feedback by continuously monitoring the state of charge of each battery cell and using this information to calculate quality factors and adjust connection probabilities. The control mechanism incorporates feedback loops where the current state informs future control decisions, enabling the system to address small state of charge differences through iterative optimization.
Data Source
AI summary
A method for connecting a plurality of battery cells of a battery, wherein the battery cells are each electrically coupled to the battery with a corresponding first probability and are each electrically decoupled from the battery with a corresponding second probability. A first quality factor is calculated for each battery cell depending on a state of charge and on a state of ageing of the corresponding battery cell. An average first quality factor, corresponding to an average value of the first quality factors of the battery cells, is also determined. A second quality factor is calculated for each battery cell as a function of the difference between the first quality factor of the corresponding battery cell and the average first quality factor. The first probability and the second probability are determined for each battery cell based on the second quality factor of the corresponding battery cell.