Battery Charging Control by SOC Resistance Change Stages
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Solution Overview
Problem
Lithium-ion batteries experience degraded cycle performance due to constant charging speed, which does not account for varying insertion resistance and potential changes during charging.
Innovation Solution
A battery charge and discharge control device and method that measures the state of charge (SOC) of a battery and adjusts the charging speed based on preset SOC sections with significant changes in insertion resistance and potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant charging speed is maintained, then charging efficiency is improved, but cycle performance deteriorates due to rapid changes in insertion resistance and potential in certain SOC stages
Solution Approach 1:
The charging speed is dynamically adjusted based on the SOC stage. The controller identifies when the battery enters a rapid change stage (when dV/dSOC or dR/dSOC exceeds threshold values) and automatically reduces charging speed during this period, then restores normal charging speed when exiting the rapid change stage, thereby adapting charging conditions to battery state
Solution Approach 2:
The system changes the charging speed parameter in response to changes in battery parameters (potential and resistance). By monitoring dV/dSOC and dR/dSOC values and comparing them against threshold values, the system switches between different charging speed modes (normal speed vs. reduced speed) to optimize both charging efficiency and cycle performance
2Reliability
If charging speed is reduced in rapid change stages, then cycle performance is improved, but charging time increases
Solution Approach 1:
The charging speed reduction is applied partially - only during specific SOC stages where rapid changes in potential or resistance occur. The controller reduces charging speed only when dV/dSOC or dR/dSOC exceeds the threshold, maintaining normal charging speed during stable stages, thus minimizing the impact on overall charging time while protecting cycle performance
Data Source
AI summary
A battery charge and discharge control device according to an embodiment of the present disclosure includes a state-of-charge (SOC) measurer measuring a SOC of a battery and a charge and discharge controller controlling a charging speed of the battery in response to the SOC of the battery being included in a preset SOC section, and the preset SOC section has change in resistance or a change in potential due to ions inserted into a material constituting the battery equal to or greater than a reference value.