Battery Charger OCV Sampling With Adaptive Relaxation Switching
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Solution Overview
Problem
Existing methods for acquiring OCV data for secondary battery degradation analysis require long relaxation times, leading to excessive time consumption and increased analytical errors when measuring at short SOC intervals.
Innovation Solution
A charger system with a measuring unit, storage unit, determination unit, charge control unit, and output unit that selectively switches between first and second modes based on terminal voltage changes, omitting OCV measurements in ranges with minimal voltage changes to reduce acquisition time while maintaining accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If intermittent charging with sufficient relaxation time is performed to acquire OCV data, then measurement precision of OCV values is improved, but loss of time increases significantly
Solution Approach 1:
The patent applies dynamics by making the relaxation time period adjustable and adaptive rather than fixed. The control unit dynamically determines the relaxation time based on battery state and charging conditions, allowing the system to optimize between measurement accuracy and acquisition time by adjusting the pause duration as needed during the charging process
Solution Approach 2:
The patent changes the parameter of relaxation time from a fixed sufficient duration to a variable parameter that can be adjusted based on battery state. By modifying the relaxation time parameter dynamically, the system achieves both reduced acquisition time and maintained measurement precision through adaptive parameter optimization
2Loss of time
If the number of SOC divisions is reduced or relaxation time is omitted to shorten acquisition time, then loss of time is reduced, but measurement precision of OCV data deteriorates
Solution Approach 1:
The system dynamically adjusts the relaxation time period based on real-time battery state and charging conditions, allowing it to maintain measurement precision while reducing overall acquisition time. The control unit makes adaptive decisions about when and how long to pause charging, optimizing the balance between speed and accuracy
Solution Approach 2:
The relaxation time parameter is transformed from a fixed value to a dynamically adjustable parameter. This allows the system to change the relaxation duration according to battery state, achieving both time reduction and precision maintenance through parameter optimization rather than simply reducing measurement points
3Measurement precision
If OCV measurements are performed at short SOC intervals to improve measurement precision, then measurement precision is improved, but productivity decreases due to excessive time consumption
Solution Approach 1:
The control unit dynamically determines relaxation time periods based on battery state and charging conditions, enabling the system to maintain short SOC intervals for high measurement precision while optimizing the time spent at each interval. This dynamic adjustment improves overall acquisition efficiency without sacrificing precision
Solution Approach 2:
By making the relaxation time a variable parameter rather than a fixed value, the system can optimize the balance between measurement frequency and time consumption. This parameter optimization enables high-productivity OCV data acquisition with short intervals while maintaining sufficient measurement precision
Data Source
AI summary
A first mode is a mode in which a secondary battery (90) is charged at a predetermined current value for a first time period, and a terminal voltage value (α) of the secondary battery (90) immediately after the lapse of the first time period is measured. A second mode is a mode in which the charging is stopped for a second time period after execution of the first mode, and an OCV value (β) of the secondary battery (90) immediately after the lapse of the second time period is measured. A determination unit (24) compares a current terminal voltage value (αA) measured in the first mode with a previous terminal voltage value (αB) measured in the immediately previous first mode. When the first time period is a (minute) and the predetermined current value is I (C), the determination unit (24) determines not to shift to the second mode in a case where αA/αB<(a×I/250)+1 (0.5≤a≤3, 0.4≤I≤2.4, and 0.6≤a×I≤1.2). The determination unit (24) determines to shift to the second mode in a case where αA/αB≥(a×I/250)+1 (0.5≤a≤3, 0.4≤I≤2.4, and 0.6≤a×I≤1.2). A measuring unit (22) measures the OCV value (β) in the second mode.