Power Storage Block Voltage Drop Rate Abnormality Detection
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Solution Overview
Problem
Existing power storage systems face delays in detecting abnormalities due to associating equalizing processes with abnormality detection, and the increased circuit size from providing every power storage cell with a voltage detection line.
Innovation Solution
A management device that identifies abnormal power storage blocks based on voltage drop rates of series-connected power storage blocks, allowing for early detection of abnormalities without the need for an equalizing process and reducing circuit size by not requiring separate voltage detection lines for each cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If every power storage cell is provided with a voltage detection line to enable early abnormality detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The power storage blocks are divided into monitoring units, with one voltage detection line per block rather than per cell. The management device segments the monitoring function to track voltage drops at the block level, which suffices for detecting abnormalities without requiring individual cell monitoring lines.
Solution Approach 2:
The voltage detection lines serve dual purposes: they monitor both normal voltage levels and detect abnormalities through voltage drop rate analysis. The same detection infrastructure supports both routine monitoring and fault detection functions, eliminating the need for separate detection lines for each cell.
2Reliability
If equalizing process is used for abnormality detection, then reliability is improved, but loss of time occurs due to delay in detection timing
Solution Approach 1:
The management device continuously monitors voltage drop rates in real-time during normal operation, rather than waiting for the equalizing process to occur. This preliminary continuous monitoring enables early abnormality detection before the equalizing process begins, eliminating the detection delay while maintaining reliability through ongoing voltage trend analysis.
Solution Approach 2:
The voltage drop rate monitoring operates continuously throughout operation, providing uninterrupted abnormality detection capability. This continuous monitoring ensures that abnormalities are detected as soon as they occur, rather than being delayed until periodic equalizing processes take place.
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
A management device manages a power storage module (20) including n series-connected power storage blocks (n: an integer of 2 or greater) each having m parallel-connected power storage cells (m: an integer of 1 or greater). In the management device, a voltage detector (11) detects voltages across the respective n power storage blocks. A storage unit (14) stores the detected voltages of the power storage blocks on a time-series basis. A voltage drop rate calculator (13a) calculates voltage drop rates of the power storage blocks based on time-series data about the voltages of the power storage blocks. An abnormality determiner (13b) determines that one of the n power storage blocks contains an abnormal power storage cell if a difference between the voltage drop rate of the one power storage block and an average value or a median value of the voltage drop rates of the remaining power storage blocks is greater than or equal to a first predetermined value.