Battery State Estimation Validation via Power Comparison
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Solution Overview
Problem
Existing battery state estimation methods for nonaqueous electrolyte secondary batteries, such as lithium ion batteries, often result in errors due to environmental factors and unforeseen current fluctuations, leading to potential malfunctions in power storage systems.
Innovation Solution
A battery state estimating apparatus comprising a state estimator, a power estimator, and a determiner that calculates internal state parameters and battery characteristics using charge curve analysis, and compares the estimated charged power amount with the input power amount to determine the validity of the estimation results, thereby preventing malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If battery state estimation is performed using conventional methods, then the power storage system can operate, but errors occur in estimation results due to environmental factors and current fluctuations
Solution Approach 1:
The patent implements a feedback mechanism by comparing the estimated charged power amount with the actual input power amount. The determiner unit continuously monitors whether the absolute value of their difference exceeds a threshold, and when it does, determines the estimation result as invalid. This closed-loop feedback system corrects estimation errors caused by environmental factors and current fluctuations, thereby improving the reliability of battery state estimation.
2Reliability
If battery state estimation is performed continuously, then monitoring reliability improves, but computational complexity and processing time increase
Solution Approach 1:
The patent applies partial action by performing validation only when necessary - specifically, by comparing estimated power amounts with actual input power amounts at intervals rather than continuously calculating all parameters. The determiner unit validates estimation results by checking whether the absolute difference between estimated and actual power amounts exceeds a threshold, reducing computational complexity while maintaining monitoring reliability.
3Measurement precision
If validation of estimation results is performed, then accuracy is improved, but additional processing steps are required
Solution Approach 1:
The patent performs preliminary validation by comparing the estimated charged power amount with the actual input power amount before finalizing the battery state estimation result. The determiner unit checks whether the absolute difference exceeds a threshold in advance, and only when the estimation is valid does it proceed with control decisions. This preliminary action prevents erroneous control based on invalid estimations while minimizing additional processing time through efficient threshold comparison.
Data Source
AI summary
A battery state estimating apparatus as an embodiment of the present invention includes a state estimator, a power estimator, and a determiner. The state estimator estimates a state of a battery. The power estimator estimates first power amount charged/discharged by the battery within a charging/discharging period, based on the state. The determiner compares the first power amount with second power amount inputted/outputted to/from the battery within the charging/discharging period and thereby determines validity of the state.