Battery Self-Discharge Detection via Charge Balance
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Solution Overview
Problem
Existing methods for detecting self-discharge faults in electric storage battery cells are unreliable and often delayed due to inefficiencies in voltage measurement and balancing, leading to rapid capacity drops or battery failure.
Innovation Solution
A method for detecting self-discharge faults by calculating the charge balance during balancing and relaxation, using equations that account for initial and final charges, discharged amounts, and error thresholds to improve detection accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage measurement method is used for detecting self-discharge faults, then detection can be implemented, but detection reliability is low and false alerts occur
Solution Approach 1:
The patent introduces charge balance calculation as an intermediary mechanism between voltage measurement and self-discharge fault detection. Instead of directly relying on voltage measurements, the system calculates charge balance during balancing and relaxation phases to indirectly detect self-discharge faults, thereby improving reliability while reducing false alerts
Solution Approach 2:
The patent implements feedback by continuously monitoring charge balance during balancing and relaxation phases. The system uses the calculated charge balance values to detect deviations indicating self-discharge faults, creating a closed-loop detection mechanism that improves reliability through continuous verification rather than single-point voltage measurement
2Measurement precision
If long relaxation time is used for voltage measurement, then detection accuracy improves, but detection timing is delayed
Solution Approach 1:
The patent performs preliminary charge balance calculations during the balancing phase before relaxation occurs. By preparing and calculating charge balance values during balancing, the system eliminates the need to wait for complete relaxation before detection can occur, thereby reducing detection delay while maintaining accuracy
Solution Approach 2:
The patent enables continuous charge balance calculation during both balancing and relaxation phases, rather than requiring a separate measurement phase. This continuous calculation approach eliminates idle time and ensures that detection can occur immediately when needed, reducing overall detection delay
3Stability of the object's composition
If dissipative balancing is used to maintain state of charge, then capacity dispersion is reduced, but self-discharge faults remain undetected
Solution Approach 1:
The patent incorporates feedback by calculating and monitoring charge balance during the dissipative balancing process. The system compares the calculated charge balance against expected values to detect deviations indicating self-discharge faults, thereby adding detection capability to the existing balancing operation without compromising state of charge uniformity
Solution Approach 2:
The patent makes the balancing system multi-functional by enabling it to perform both its original function (maintaining state of charge uniformity through dissipative balancing) and a new function (detecting self-discharge faults through charge balance calculation). This eliminates the need for separate detection mechanisms while preserving the stabilizing effect of balancing
Data Source
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AI summary
Said method is used for detecting, in an electric storage battery (10) having a plurality of battery cells (1, 2, 3, 4), a self-discharge defect in a cell (1, 2, 3, 4), wherein: a charge balancing of the battery cells (1, 2, 3, 4) is at least partially carried out, a relaxation of the battery cells (1, 2, 3, 4) is performed, a charge balance during the balancing and relaxation (Σi) of said cell (i) is calculated for each battery cell (i), and any self-discharge defects of said cell (i) are detected for each battery cell (i) depending on the charge balance calculated for said cell (i) during the balancing and relaxation (∑i).