Secondary Battery State Detection Device with Variable Threshold
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Solution Overview
Problem
Conventional methods for detecting a full charge in secondary batteries are inaccurate when the charging voltage supplied by an alternator varies, as they assume a constant voltage, leading to inefficiencies in fuel consumption.
Innovation Solution
A secondary battery state detection device and method that adjusts the detection threshold based on the alternator's adjustable voltage, calculating the charging resistance and estimating the state of charge using a variable or fixed threshold to accurately determine full charge or predetermined states even when the alternator's voltage changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional full charge detection methods are used that assume constant voltage, then the detection process is simple, but the detection accuracy deteriorates when alternator voltage varies
Solution Approach 1:
The patent applies dynamics by making the detection threshold variable rather than fixed. The threshold is dynamically adjusted based on the actual charging voltage from the alternator, allowing the system to maintain high detection accuracy across varying voltage conditions. This is achieved by calculating a voltage-specific threshold that adapts to the current charging state.
Solution Approach 2:
The patent changes the parameter of the detection threshold from a constant value to a voltage-dependent variable. By establishing a relationship between charging voltage and appropriate detection thresholds, the system can accurately determine full charge status across different voltage conditions. This parameter change enables the detection method to adapt to varying alternator output without increasing hardware complexity.
2Measurement precision
If the detection threshold is adjusted based on charging voltage to improve accuracy, then detection precision improves, but computational complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing detection thresholds for different charging voltage levels. Instead of performing complex real-time calculations during charging, the system has thresholds prepared in advance based on the voltage-state of charge relationship. During operation, it simply looks up the appropriate threshold based on current voltage, significantly reducing computational burden while maintaining high accuracy.
3Loss of energy
If charging control is optimized to reduce fuel consumption, then energy efficiency improves, but charging performance may deteriorate
Solution Approach 1:
The patent applies feedback by continuously monitoring the charging voltage and comparing the actual state of charge against voltage-specific thresholds. This feedback mechanism allows the system to optimize alternator operation - stopping charging at the appropriate moment based on accurate detection, thereby reducing unnecessary fuel consumption. The feedback loop ensures that charging performance is maintained by preventing premature termination while eliminating wasteful extended charging.
Data Source
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AI summary
[Problem] Accurately detecting a full charge of a secondary battery even in cases in which a voltage generated by an alternator changes. [Solution] A secondary battery state detection device 1 for detecting the state of a secondary battery includes at least one processor (CPU 10a) and at least one memory (ROM 10b, RAM 10c) that is communicably connected to the at least one processor. The at least one processor reads a set of instructions stored in the at least one memory, and executes detection process in which a charging voltage is detected, the charging voltage being generated when an alternator that generates an adjustable voltage charges the secondary battery; computation process in which a charging resistance is calculated as an internal resistance of the secondary battery when the alternator charges the secondary battery; and estimation processing in which a state of charge of the secondary battery is estimated on the basis of the charging voltage detected by the detection process and on the charging resistance calculated by the computation process.