Battery Class Determination via Inner Resistance
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Solution Overview
Problem
Conventional battery class determination methods for lead storage batteries are inaccurate due to variations in electric-current waveforms caused by temperature and state of charge (SOC), which affects proper classification and functionality, especially in idling stop systems.
Innovation Solution
A battery class determination device that calculates direct-current inner resistance in both discharge and charge periods, using a detector to sense terminal voltage and charge/discharge currents, and a class determiner to accurately classify the battery based on these resistances, ensuring accurate identification of battery compatibility with idling stop systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional battery class determination method using electric-current waveform is used, then the determination process is simple, but the determination accuracy deteriorates due to waveform variations caused by temperature and SOC
Solution Approach 1:
The patent changes the measurement parameter from electric-current waveform to direct-current inner resistance. This parameter change eliminates the sensitivity to temperature and SOC variations, thereby improving determination accuracy without significantly increasing system complexity. The inner resistance is calculated using terminal voltage and charge/discharge current, which are already available in the system.
Solution Approach 2:
The patent replaces the conventional waveform-based determination method with an electrical parameter-based method (inner resistance calculation). This substitution uses electrical measurements (terminal voltage and current) to derive inner resistance, replacing the need for complex waveform analysis and improving accuracy while maintaining simplicity.
2Reliability
If lead storage battery with poor performance is used in idling stop system, then cost is reduced, but system reliability deteriorates
Solution Approach 1:
The patent performs preliminary determination of battery class before the idling stop system is activated. By calculating the inner resistance in advance and determining whether the battery meets the required specifications, the system prevents reliability issues before they occur. This allows proper battery selection without requiring expensive batteries, as long as the performance is verified in advance.
Solution Approach 2:
The patent implements a feedback mechanism where the determined battery class information is fed back to the idling stop control. This feedback allows the control system to adjust its operation based on the actual battery performance, ensuring reliable operation even with cost-effective batteries that meet the minimum specifications.
3Measurement precision
If battery class determination is performed under varying temperature and SOC conditions, then measurement flexibility is improved, but measurement precision deteriorates
Solution Approach 1:
The patent changes the measurement approach from direct waveform analysis to inner resistance calculation based on terminal voltage and current measurements. This parameter change makes the measurement insensitive to temperature and SOC variations, achieving high precision while maintaining flexibility in measurement conditions. The inner resistance can be accurately determined regardless of when or under what conditions the measurement is taken.
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
Enables precise classification of lead storage batteries, preventing misclassification and ensuring proper system functionality, thereby reducing battery-related issues and improving vehicle performance and compliance with inspection standards.
Implementation Method 1
an inner resistance calculator that calculates a direct-current inner resistance of the lead storage battery based on the terminal voltage and the charge or discharge current sensed by the detector
Data Source
AI summary
A battery class determination device includes a detector for sensing a terminal voltage and charge/discharge currents of a lead storage battery, an inner resistance calculator for calculating a direct-current inner resistance of the lead storage battery based on the terminal voltage and the charge or discharge current sensed by the detector, and a class determiner. The inner resistance calculator calculates, at a switchover between a discharge control and a charge control over the lead storage battery, a direct-current inner resistance in a first period before the switchover, and a direct-current inner resistance in a second period after the switchover. The class determiner determines a class of the lead storage battery based on the direct-current inner resistance in the first period and the direct-current inner resistance in the second period.