Dynamic Threshold Battery Short Circuit Detection
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Solution Overview
Problem
Existing rechargeable battery abnormality detection systems often falsely detect voltage drops due to self-discharge as internal short circuits in degraded batteries, leading to premature rejection of batteries that still retain charging capability.
Innovation Solution
A rechargeable battery abnormality detection apparatus that monitors voltage changes during no charging or discharging, detects internal short circuits by exceeding a preset threshold voltage, and adjusts this threshold based on battery degradation factors like capacity change, cycle count, and internal resistance to differentiate between self-discharge and short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed threshold voltage is used to detect internal short circuits, then detection simplicity is maintained, but false detection increases in degraded batteries due to self-discharge voltage drop
Solution Approach 1:
The threshold voltage is changed from a fixed value to a dynamic value that automatically adjusts based on battery degradation level. The system determines the threshold voltage according to the degree of battery degradation, allowing the detection threshold to adapt to different battery states and prevent false detections in degraded batteries.
Solution Approach 2:
The detection threshold parameter is modified based on battery degradation characteristics. By changing the threshold voltage parameter according to the determined degradation degree, the system maintains accurate internal short circuit detection while accommodating the increased self-discharge effects in degraded batteries.
2Measurement precision
If internal short circuit detection is performed using voltage drop monitoring, then detection capability is achieved, but premature battery rejection occurs due to false detection in degraded batteries
Solution Approach 1:
The system dynamically adjusts the voltage drop threshold based on battery degradation level. For degraded batteries showing larger self-discharge voltage drops, the threshold is increased accordingly, preventing false positive detections while maintaining sensitivity to actual internal short circuits.
Solution Approach 2:
The system uses feedback from battery performance monitoring to continuously refine the threshold voltage setting. By monitoring battery degradation over time and adjusting the threshold accordingly, the system learns to distinguish between normal self-discharge in degraded batteries and abnormal voltage drops indicating internal short circuits.
3Measurement precision
If the detection threshold is lowered to improve internal short circuit detection sensitivity, then detection sensitivity increases, but false detection rate increases due to self-discharge in degraded batteries
Solution Approach 1:
The threshold parameter is adjusted based on battery degradation state. For new batteries with low self-discharge, a lower threshold provides high sensitivity. For degraded batteries with higher self-discharge, the threshold is increased to match the elevated baseline, maintaining sensitivity while reducing false detections.
Solution Approach 2:
Different threshold values are applied to different battery degradation states. Rather than using a single universal threshold, the system implements local optimization by setting appropriate thresholds for each degradation level, ensuring high sensitivity where appropriate while avoiding false alarms in degraded batteries.
Data Source
AI summary
The rechargeable battery abnormality detection apparatus is provided with an internal short circuit detection section (20b) that monitors rechargeable battery (1) voltage change when no charging or discharging takes place, and detects internal short circuit abnormality when battery voltage drop during a predetermined time period exceeds a preset threshold voltage; a degradation appraisal section (20d) that judges the degree of rechargeable battery degradation; and a threshold control section (20c) that incrementally increases the threshold voltage according to the degree of degradation determined by the degradation appraisal section (20d).