Battery Management Device Detecting Abnormal Cells via Equalizing
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Solution Overview
Problem
Current methods for detecting open failures in cells within multiple series-parallel power storage modules are either slow or require vehicle travel, leading to low detection accuracy and potential sudden vehicle stops due to battery abnormalities.
Innovation Solution
A management device with a voltage detection circuit, equalizing circuits, and a controlling circuit that detects voltage changes during discharging or charging to identify abnormal cells within the power storage module, allowing for accurate detection before vehicle travel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If voltage deviation method is used to detect abnormal parallel cell groups, then detection can be performed without current flow, but detection accuracy is low due to small resistance fluctuation
Solution Approach 1:
The system performs preliminary equalizing processes before main charging to create detectable voltage changes. By预先 equalizing the parallel cell groups, the system amplifies the voltage differences that would otherwise be too small to detect accurately, enabling accurate detection without requiring current flow during the detection phase.
2Measurement precision
If power difference method based on integrated current is used, then detection accuracy improves, but vehicle must be traveling which causes phase shift and delays detection
Solution Approach 1:
The system performs detection during preliminary equalizing processes that occur before the vehicle starts traveling. This preliminary detection phase allows accurate identification of abnormal cell groups while the vehicle is still stationary, preventing delayed detection and avoiding the phase shift problems that occur during vehicle travel.
Solution Approach 2:
The charging process is segmented into preliminary equalizing processes and main charging. The detection is performed during the preliminary phase when conditions are favorable (vehicle stationary, no phase shift), separating the detection function from the main charging operation to optimize both accuracy and timing.
3Power
If multiple series-parallel power storage module is used to achieve high voltage and high capacity, then power supply performance improves, but open failure risk increases due to more cells
Solution Approach 1:
The power storage module is divided into multiple parallel cell groups connected in series, with each group containing multiple parallel cells. This segmentation allows individual monitoring and equalizing of each parallel group, enabling early detection of open failures in specific cells while maintaining the overall high voltage and high capacity configuration.
Solution Approach 2:
The system continuously monitors voltage changes in each parallel cell group during equalizing processes and provides feedback to the controlling circuit. When voltage deviation exceeds thresholds, the system identifies potential open failures and can adjust charging strategies, creating a feedback loop that maintains reliability in the high-power multiple series-parallel configuration.
Data Source
AI summary
Provided is a management device that manages a power storage module configured by connecting in series a plurality of parallel cell groups in which a plurality of cells are connected in parallel. In the management device, a voltage detection circuit detects a voltage of each of the plurality of parallel cell groups connected in series. A plurality of equalizing circuits are connected in parallel to the plurality of parallel cell groups, respectively. A controlling circuit controls the plurality of equalizing circuits based on the voltage detected by the voltage detection circuit and executes an equalizing process. The controlling circuit determines whether or not an abnormal cell is included in each of the parallel cell groups based on a voltage change of each of the parallel cell groups during discharging to the equalizing circuit or charging from the equalizing circuit.