Battery Internal Resistance Estimation via Selective Data Filtering
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Solution Overview
Problem
Existing methods for estimating internal resistance of battery packs do not effectively utilize current change conditions and voltage, temperature values to accurately calculate internal resistance, which is crucial for efficient battery management in electric and hybrid vehicles.
Innovation Solution
An apparatus and method that include a voltage sensing unit, current sensing unit, temperature sensing unit, and microprocessor unit (MCU) to measure and calculate internal resistance by extracting current values satisfying a set condition, storing corresponding voltage and temperature values, and using these to estimate internal resistance through repeated measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If internal resistance is calculated using standard least squares method with all current and voltage measurements, then calculation can be performed continuously, but measurement precision is insufficient due to inclusion of irrelevant data points
Solution Approach 1:
The patent extracts only the relevant current and voltage data points that satisfy specific measurement conditions (current change rate within threshold, voltage change rate within threshold, current above threshold) from the complete measurement dataset. This extraction process eliminates irrelevant data points that would otherwise degrade the precision of internal resistance calculation, while maintaining a manageable dataset size for the least squares computation.
Solution Approach 2:
The patent applies different quality criteria to different phases of the measurement process. During data collection, all measurements are recorded without discrimination. During data processing, a selective filtering mechanism applies local quality standards to identify only those data points meeting the predefined conditions. This local quality approach ensures high precision calculations while avoiding the complexity of continuously evaluating all data points.
2Measurement precision
If multiple current and voltage values are collected and stored for repeated measurements, then internal resistance estimation precision improves, but data storage requirements and processing time increase
Solution Approach 1:
The patent performs preliminary filtering and selection of data points that meet the measurement conditions before the actual internal resistance calculation. By pre-identifying and storing only the relevant current and voltage pairs in the dataset, the system prepares optimized input data for the least squares calculation, reducing the computational burden during the estimation phase while ensuring high precision through multiple valid data points.
3Measurement precision
If current values satisfying specific change conditions are selected for calculation, then measurement precision improves, but the complexity of judging measurement conditions increases
Solution Approach 1:
The patent implements a feedback mechanism where each newly acquired current and voltage measurement is immediately evaluated against the predefined conditions (current change rate threshold, voltage change rate threshold, minimum current threshold). The system provides feedback by either accepting the measurement for inclusion in the calculation dataset or rejecting it. This real-time feedback approach maintains measurement precision through selective data inclusion while using a systematic, rule-based evaluation process that manages the complexity of condition judgment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for precise estimation of internal resistance, enhancing battery management, predicting replacement times, and aiding in after-sales services and state control for electric and hybrid vehicles.
Implementation Method 1
a voltage sensing unit that measures a voltage value of the battery pack
Implementation Method 2
a current sensing unit that measures a current value of the battery pack
Implementation Method 3
a temperature sensing unit that measures a temperature value of the battery pack
Implementation Method 4
a microprocessor unit (MCU) that calculates the internal resistance of the battery pack using values transferred from the voltage sensing unit, the current sensing unit, and the temperature sensing unit
Data Source
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AI summary
Provided are an apparatus and a method for estimating internal resistance of a battery pack. The apparatus includes: a voltage sensing unit that measures a voltage value of the battery pack; a current sensing unit that measures a current value of the battery pack; a temperature sensing unit that measures a temperature value of the battery pack; and a microprocessor unit (MCU) that calculates the internal resistance of the battery pack using values transferred from the voltage sensing unit, the current sensing unit, and the temperature sensing unit.