Battery Charging Rate Estimation with Hysteresis-Aware OCV Averaging
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Solution Overview
Problem
Conventional methods for estimating battery charging rate accuracy deteriorate with battery degradation, particularly in batteries with large charge/discharge hysteresis, such as those using Si as a negative electrode active material.
Innovation Solution
A method involving the acquisition of an SOC-OCV curve line, calculation of average voltage, recording of SOC-OCV relation, and performing return charging and discharging steps to accurately estimate the charging rate by measuring OCV against the recorded relation, even in deteriorated batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional SOC estimation methods are used, then the estimation process is simple, but the estimation accuracy deteriorates when the battery deteriorates or has large charge/discharge hysteresis
Solution Approach 1:
The method performs preliminary actions by conducting continuous charging or discharging followed by return discharging or charging to eliminate polarization before measuring OCV. This preliminary treatment ensures the battery reaches a stable state, allowing accurate SOC estimation even when the battery deteriorates or has large hysteresis, without requiring complex real-time correction algorithms.
Solution Approach 2:
The method implements periodic action by suspending charging/discharging for a predetermined period to allow the battery to stabilize and eliminate polarization effects. This periodic suspension enables accurate OCV measurement and SOC estimation while maintaining a relatively simple overall process structure.
2Measurement precision
If continuous charging or discharging is performed without suspension, then the process is efficient, but polarization effects reduce estimation accuracy
Solution Approach 1:
The method applies partial action by suspending charging/discharging for just a predetermined period sufficient to eliminate polarization effects, rather than requiring complete stabilization or extended waiting times. This approach achieves accurate OCV measurement while minimizing time loss, balancing measurement precision with process efficiency.
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
Maintains accurate estimation of battery charging rate despite deterioration, especially in batteries with large hysteresis, by eliminating polarization through suspension periods and averaging voltage phases.
Implementation Method 1
a battery of which a charge/discharge hysteresis Δ is 0.06V to 0.24V
Implementation Method 2
acquiring an SOC-OCV curve line for a battery having a charge/discharge hysteresis of Δ0.06V to 0.24V
Implementation Method 3
batteries with large charge/discharge hysteresis (for example, when Si is used as a negative electrode active material)
Data Source
AI summary
A method for estimating a charging rate of a battery including: acquiring an SOC-OCV curve line for the battery having a charge/discharge hysteresis of Δ0.06V to 0.24V, calculating an average voltage of OCV for each SOC from the acquired result, and recording the relation between the calculation result and the SOC; performing continuous charging or continuous discharging on the battery; performing return discharging that is discharging of 3% or more of a total capacity of the battery when the continuous charging has been performed, and performing return charging that is charging of 3% or more of the total capacity of the battery when the continuous discharging has been performed; and measuring the OCV of the battery and checking the value of the OCV against the recorded relation between the SOC and the average voltage of the OCV to acquire an estimated value of the charging rate of the battery.