Battery Cell Voltage Balance Control via Minimum Value Threshold
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Solution Overview
Problem
Large-scale storage battery systems face challenges in maintaining cell balance and preventing voltage fluctuations due to abnormal conditions in battery cells, which can lead to reduced utilization and inefficiencies in natural energy power generation systems.
Innovation Solution
A storage battery management device with a minimum value determination unit and controller that adjusts cell balance by setting a target voltage based on the minimum cell voltage within acceptable differences across battery units, preventing the influence of abnormal cells and enhancing system utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the voltage of a single battery cell having the lowest voltage is used as a target voltage to adjust the voltage of other single battery cells, then the cell balance is adjusted, but abnormally low voltage in a battery cell can cause all cells to be adjusted to the abnormal voltage level
Solution Approach 1:
The patent introduces an intermediary mechanism (voltage difference threshold judgment) between the abnormal cell detection and the cell balance adjustment process. By comparing the voltage difference between the lowest voltage cell and other cells against a predetermined threshold, the system acts as a mediator to determine whether to proceed with adjustment, thereby preventing abnormal cells from directly influencing the entire system's voltage level
Solution Approach 2:
The patent extracts and isolates the abnormal cell from the cell balance adjustment process. When a cell is identified as having abnormally low voltage (below the threshold), it is excluded from the adjustment calculation, allowing the remaining normal cells to be balanced without being dragged down to the abnormal voltage level
2Productivity
If multiple battery units are managed to increase storage capacity, then system utilization is enhanced, but voltage fluctuations and cell balance issues can propagate across units
Solution Approach 1:
The patent segments the multi-unit battery system into independent monitoring and control zones. Each battery unit's cell balance adjustment is performed independently with its own threshold judgment, preventing voltage fluctuations and balance issues in one unit from propagating to other units while maintaining overall system utilization
Data Source
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AI summary
A storage battery management device according to an embodiment manages a plurality of battery units in a storage battery system including the battery units having a plurality of battery cells and a power adjustment device connected to the battery units via respective contactors and to a main circuit. In the management device, a minimum value determination unit, from the battery units in which a difference between the maximum and the minimum cell voltages of the battery cells forming each of the battery units, determines the minimum value of the minimum cell voltage, and a controller controls a cell balance process of the battery unit managed by itself by using the minimum value of the minimum cell voltage as a cell balance target voltage. Even if an abnormality occurs in any battery cell (or cell module) forming the battery units, this configuration can prevent an influence and provide enhanced utilization.