Battery Charging Control Using Rest Period Resistance Tracking
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Solution Overview
Problem
Fast charging of battery cells can cause significant damage, including lithium plating, which reduces the life of the battery and increases the risk of explosion and fire, due to the accumulation of lithium ions on the negative electrode.
Innovation Solution
An apparatus and method that alternately repeats charging and resting modes to calculate internal resistance and monitor changes in resistance, deriving the depth of charge (DOC) to avoid lithium plating by obtaining battery cell characteristic information through electrochemical impedance spectroscopy (EIS).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fast charging is performed to reduce charging time, then charging speed is improved, but lithium plating occurs causing safety issues and reduced battery life
Solution Approach 1:
The patent implements periodic action by alternating between charging mode and resting mode during the charging process. The controller switches between these modes based on predetermined conditions, allowing the battery to rest periodically and dissipate heat, thereby preventing lithium plating while maintaining efficient charging overall. This periodic interruption of continuous charging resolves the contradiction between charging speed and battery safety.
2Reliability
If intermittent charging with resting mode is implemented to prevent lithium plating, then battery safety is improved, but charging time increases
Solution Approach 1:
The patent applies partial action by implementing resting mode only under specific conditions rather than continuously. The controller determines when to switch to resting mode based on charging progress conditions, and the duration of resting mode is controlled to be just sufficient to prevent lithium plating without unnecessarily extending charging time. This selective application of resting mode balances safety requirements with charging 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
This approach allows for accurate estimation of internal resistance and DOC, preventing lithium plating and ensuring the safety and longevity of battery cells by optimizing the charging process.
Implementation Method 1
a voltage sensor configured to detect the voltage of a battery cell
Implementation Method 2
an operation of determining the internal resistance of the battery cell based on an amount of change in voltage of the battery cell in a resting period where the resting mode continues
Data Source
AI summary
The charging control apparatus according to the present disclosure includes a voltage sensor configured to detect the voltage of a battery cell and a controller configured to execute an intermittent charging process to alternately repeat a charging mode and a resting mode for the battery cell. Under the condition that the charging mode is switched to the resting mode while the intermittent charging process is being executed, the controller is configured to execute: an operation of determining an internal resistance of the battery cell based on an amount of change in voltage of the battery cell in a resting period where the resting mode continues; and an operation of recording the internal resistance in association with SOC of the battery cell.