Battery Lifetime Estimation via Partial Discharge Voltage Drop
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Solution Overview
Problem
Existing methods struggle to accurately estimate the remaining lifetime of batteries in use, especially in real-time, due to difficulties in measuring State of Health (SOH) and Remaining Useful Lifetime (RUL) during partial charging and discharging, and variations in battery performance across different environments.
Innovation Solution
A battery lifetime estimating method that involves fully charging a battery, partially discharging it, acquiring voltage information at multiple time points, and applying a particle filter to estimate the remaining capacity, using voltage drop amounts to calculate the battery's capacity and predict its remaining lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fully charging/discharging operation is performed to measure SOH, then measurement accuracy is improved, but it becomes impossible to perform measurement at site and difficult to apply to real-time lifetime estimation
Solution Approach 1:
The patent applies partial action by performing only a partial discharge (not full discharge) after full charging to estimate battery capacity. This partial discharge operation, combined with voltage drop measurement, provides sufficient information for SOH estimation without requiring complete charging/discharging cycles, thus enabling site-based real-time measurement while maintaining acceptable accuracy.
Solution Approach 2:
The patent applies preliminary action by first fully charging the battery before performing the partial discharge operation. This preliminary full charging ensures the battery starts from a known state (100% SOC), which is necessary for accurate capacity estimation through voltage drop measurement during subsequent partial discharge, while still avoiding the need for full discharge.
2Device complexity
If battery lifetime estimation is performed without considering environmental factors and cell deviations, then device complexity is reduced, but estimation accuracy deteriorates
Solution Approach 1:
The patent applies feedback by using the particle filter method, which is a statistical technique that processes sequential measurements and updates probability distributions based on new data. This feedback mechanism allows the estimation to adapt to environmental variations and cell deviations by continuously refining the lifetime prediction based on actual voltage drop measurements, thereby improving accuracy without requiring complex manual adjustments.
Solution Approach 2:
The patent introduces a statistical technique (particle filter) as an intermediary between the simple voltage drop measurement and the complex reality of battery degradation. This intermediary method bridges the gap by mathematically accounting for environmental factors and cell variations without requiring direct measurement of each factor, thus maintaining relative simplicity while improving estimation accuracy.
3Measurement precision
If voltage information is acquired at multiple measurement time points, then estimation accuracy is improved, but measurement time and complexity increase
Solution Approach 1:
The patent applies partial action by selecting specific measurement time points during the discharge process rather than continuous monitoring. By measuring voltage at key moments (such as at predetermined time intervals or at specific discharge depths), the method captures sufficient information for accurate capacity estimation while minimizing the total measurement time and processing complexity.
Data Source
AI summary
Provided is a battery lifetime estimating method including steps of: fully charging a battery according to a predetermined charging condition; partially discharging the fully charged battery according to a predetermined discharging condition; acquiring voltage information at a plurality of predetermined measurement time points while performing the partially discharging; and estimating a remaining capacity of the battery by using the acquired voltage information. Herein, the step of estimating the remaining capacity of the battery includes steps of: calculating the capacity of the battery in one cycle of fully charging/discharging in which the measurement is performed from the measured voltage drop amounts; and estimating the remaining lifetime of the battery by applying a statistical technique to the capacity of the battery calculated with respect to a plurality of cycles of fully charging/discharging.