Battery Cell Voltage Diagnosis Using Rest-Section Statistical Analysis
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Solution Overview
Problem
Existing battery diagnosis systems fail to accurately identify the type of error occurring in a battery cell based on its voltage, which can lead to potential damage to the battery and associated devices.
Innovation Solution
A battery diagnosis device that includes a voltage measurement circuit, data processing circuit, and diagnosis circuit to periodically measure and analyze voltage differences, using statistical values and fitting equations to determine the type of error, such as instability, temporary voltage rise, or drop, by comparing cumulative and absolute statistical values with reference values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple voltage measurement is used, then device complexity is reduced, but measurement precision and error identification accuracy deteriorate
Solution Approach 1:
The patent segments the voltage analysis process into multiple components: raw voltage measurement, fitting value calculation using empirical equations, statistical value derivation, and cumulative statistical value accumulation. This segmentation allows each component to be optimized independently while maintaining overall system manageability and accuracy.
Solution Approach 2:
The patent transitions from one-dimensional voltage measurement to multi-dimensional analysis by introducing time dimension (multiple rest sections), statistical dimension (standard deviation, mean values), and cumulative dimension (accumulated statistical values). This dimensional expansion enables precise error identification without proportionally increasing device complexity.
2Measurement precision
If comprehensive statistical analysis is performed, then error identification accuracy is improved, but loss of time increases
Solution Approach 1:
The patent performs preliminary actions by pre-calculating fitting values using empirical equations during the charging and discharging phases, and by pre-establishing reference ranges for statistical values. This preparation work is done in advance so that the actual error identification during rest sections requires minimal computation time.
Solution Approach 2:
The patent implements periodic voltage measurements during rest sections rather than continuous monitoring. By analyzing voltage at specific periodic intervals (rest sections after charging and discharging), the system achieves accurate error identification while minimizing the total time required for analysis.
3Reliability
If multiple rest sections are analyzed, then reliability of error diagnosis is improved, but loss of time increases
Solution Approach 1:
The patent applies partial action by analyzing only the necessary number of rest sections (typically one or two) rather than all possible rest sections. The cumulative statistical value accumulates data from multiple rest sections, but the diagnosis can be made after a sufficient number of sections have been analyzed, balancing reliability with time efficiency.
Solution Approach 2:
The patent uses feedback mechanisms where the cumulative statistical value is continuously updated with each rest section analysis. The system monitors the accumulation process and can determine when sufficient reliability has been achieved, allowing dynamic adjustment of the analysis duration based on the evolving diagnostic confidence.
Data Source
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AI summary
The present invention provides a battery diagnosis device for diagnosing a type of error occurring in a battery cell based on the voltage of the battery cell. A battery diagnosis device includes a voltage measurement circuit, a data processing circuit and a diagnosis circuit. The voltage measurement circuit periodically measures the voltage at both ends of the battery cell in the rest section. The data processing circuit derives a statistical value indicating the state of the battery cell based on difference values between the voltage values measured by the voltage measurement circuit and fitting values calculated based on the measured voltage values. The diagnosis circuit determines whether an error has occurred in the battery cell based on statistical values in a plurality of rest sections, and determines whether the type of error is a first type in which the battery cell is unstable, a second type in which the voltage of the battery cell temporarily rises, or a third type in which the voltage of the battery cell temporarily drops based on a cumulative statistical value in which an absolute values of the statistical values are accumulated and the statistical value in the rest section. The plurality of rest sections include a rest section and one or more rest sections before the rest section.