Battery OCV Pattern Estimation for Degradation Acceleration
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Solution Overview
Problem
Current battery state estimation methods only provide information on past or present degradation, failing to predict future battery performance or lifetime, and do not offer specific insights into degradation acceleration rates.
Innovation Solution
A battery state estimating apparatus that measures open circuit voltage (OCV) and internal resistance, calculates voltage and resistance fluctuation rates, and determines degradation acceleration patterns to predict future battery degradation, classifying it as accelerated, linear, or decelerated degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If conventional battery state estimation methods are used, then the degradation degree can be determined, but specific information on degradation acceleration and future battery state cannot be provided
Solution Approach 1:
The patent segments the degradation assessment into multiple dimensions: degradation degree (based on full charge capacity loss), voltage fluctuation rate, and resistance fluctuation rate. Each dimension is measured and analyzed separately to provide comprehensive degradation information, including both current state and acceleration trends.
Solution Approach 2:
The patent performs preliminary measurements of voltage and resistance fluctuations during the charging process before the battery reaches full charge. These preliminary actions enable the calculation of fluctuation rates that predict future degradation acceleration, allowing proactive battery management rather than reactive assessment.
2Reliability
If only full charge capacity measurement is used, then degradation degree can be calculated, but degradation rate and future lifetime prediction are not available
Solution Approach 1:
The patent implements a feedback mechanism where voltage and resistance measurements during charging are continuously monitored, and the calculated fluctuation rates feed back into the degradation assessment model. This feedback loop enables real-time updates of degradation degree and acceleration predictions, improving reliability while reducing the time needed for accurate forecasting.
Solution Approach 2:
By performing voltage and resistance measurements during the charging process itself (before full charge is reached), the system obtains preliminary data that enables immediate calculation of degradation metrics and future state predictions, eliminating the need for separate testing phases and reducing overall assessment time.
3Measurement precision
If voltage and resistance fluctuation rates are calculated, then degradation acceleration can be determined, but measurement complexity increases
Solution Approach 1:
The patent makes the battery management system multi-functional by enabling it to perform multiple tasks: measuring full charge capacity, calculating voltage fluctuation rates, calculating resistance fluctuation rates, determining degradation degree, and predicting future degradation acceleration. This universal approach consolidates multiple measurement functions into a single integrated system, reducing overall complexity despite the increased capabilities.
Solution Approach 2:
The patent merges the measurement of voltage and resistance fluctuations with the existing full charge capacity measurement process. By combining these measurements into a unified degradation assessment framework, the system achieves high measurement precision without proportionally increasing device complexity, as all measurements are performed within the same charging management architecture.
Data Source
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AI summary
A battery state estimating apparatus according to an embodiment of the present disclosure includes: a voltage measuring unit configured to measure a voltage of a battery cell and measure an open circuit voltage (OCV) of the battery cell whenever the measured voltage reaches a reference charge voltage; and a control unit configured to receive the OCV measured by the voltage measuring unit, calculate a voltage fluctuation rate based on a result obtained by processing the received OCV, determine a voltage increase and decrease pattern based on the calculated voltage fluctuation rate and pre-stored voltage fluctuation rate data, and determine a degradation acceleration degree of the battery cell according to the determined voltage increase and decrease pattern.