SOC-Based Charge Control for Rapid Charging Without Capacity Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rapid charging of lithium secondary batteries can lead to a decrease in discharge capacity due to the formation of a low-density lithium layer at the negative electrode, which increases the battery's thickness and reduces the amount of active metallic lithium, causing it to react more readily with the electrolyte.
Innovation Solution
A charge control device that sets permitted charging current/power values based on the State of Charge (SOC) actual value and the rapid charging start SOC value, adjusting the charging conditions to prevent a reduction in discharge capacity by switching between first and second charging conditions depending on the SOC value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If rapid charging is performed with large current, then charging time is reduced, but discharge capacity decreases due to low-density lithium layer formation
Solution Approach 1:
The charging current is dynamically adjusted based on the SOC value. When SOC is at or below the rapid charging start SOC value, a first charging condition with higher current is applied to enable rapid charging. When SOC exceeds this threshold, a second charging condition with lower current is applied to prevent low-density lithium layer formation, thus maintaining discharge capacity while minimizing charging time.
Solution Approach 2:
The invention changes the charging current parameter based on the SOC state. By switching between two distinct charging conditions (first charging condition with higher current, second charging condition with lower current) based on the SOC value relative to the rapid charging start SOC value, the system optimizes both charging speed and battery health.
2Speed
If rapid charging is performed, then charging speed increases, but lithium layer density decreases forming porous structure
Solution Approach 1:
The charging current is dynamically adjusted based on the SOC value. When SOC is at or below the rapid charging start SOC value, a first charging condition with higher current is applied to enable rapid charging. When SOC exceeds this threshold, a second charging condition with lower current is applied to prevent low-density lithium layer formation, thus maintaining discharge capacity while minimizing charging time.
Solution Approach 2:
The invention changes the charging current parameter based on the SOC state. By switching between two distinct charging conditions (first charging condition with higher current, second charging condition with lower current) based on the SOC value relative to the rapid charging start SOC value, the system optimizes both charging speed and battery health.
3Loss of time
If rapid charging is performed with low-density lithium layer, then charging time is reduced, but negative electrode thickness increases
Solution Approach 1:
The charging current is dynamically adjusted based on the SOC value. When SOC is at or below the rapid charging start SOC value, a first charging condition with higher current is applied to enable rapid charging. When SOC exceeds this threshold, a second charging condition with lower current is applied to prevent low-density lithium layer formation, thus maintaining discharge capacity while minimizing charging time.
Solution Approach 2:
The invention changes the charging current parameter based on the SOC state. By switching between two distinct charging conditions (first charging condition with higher current, second charging condition with lower current) based on the SOC value relative to the rapid charging start SOC value, the system optimizes both charging speed and battery health.
4Productivity
If rapid charging is performed, then charging efficiency increases, but metallic lithium reacts more with electrolyte reducing active lithium amount
Solution Approach 1:
The charging current is dynamically adjusted based on the SOC value. When SOC is at or below the rapid charging start SOC value, a first charging condition with higher current is applied to enable rapid charging. When SOC exceeds this threshold, a second charging condition with lower current is applied to prevent low-density lithium layer formation, thus maintaining discharge capacity while minimizing charging time.
Solution Approach 2:
The invention changes the charging current parameter based on the SOC state. By switching between two distinct charging conditions (first charging condition with higher current, second charging condition with lower current) based on the SOC value relative to the rapid charging start SOC value, the system optimizes both charging speed and battery health.
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 rapid charging while maintaining the battery's discharge capacity by adjusting charging currents according to the SOC value, preventing the formation of low-density lithium layers and extending the battery's life.
Implementation Method 1
a study has been conducted on controlling the charging current to allow lithium to be deposited on the negative electrode
Data Source
AI summary
The charge control device of the present invention includes a charging condition setter that compares a State of Charge (SOC) actual value being a current SOC value of a battery with a rapid charging start SOC value being an SOC value of the battery at a time of previously starting rapid charging by an external power source, and sets a first charging condition when the SOC actual value is equal to or less than the rapid charging start SOC value; and a charge controller that charges the battery under a charging condition that is set by the charging condition setter.