Battery Charging Current Control Using SOC-Entropy Mapping
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Solution Overview
Problem
The challenge of battery deterioration during quick charging in non-aqueous electrolyte secondary batteries, particularly lithium ion batteries, is not effectively addressed by existing technologies, leading to reduced battery life and increased charging times.
Innovation Solution
A method that estimates the state of charge (SOC) of the battery based on voltage and current, and determines the charging current in relation to the entropy change of the battery reaction, setting it higher in regions where entropy change is positive to suppress deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If quick charging with large current is applied to shorten charging time, then charging speed is improved, but battery deterioration accelerates
Solution Approach 1:
The charging current is dynamically adjusted based on real-time entropy change measurements. The system continuously monitors entropy change during charging and adapts the charging current accordingly, transitioning from static current profiles to dynamic current control that responds to battery state changes.
Solution Approach 2:
The invention changes the charging current parameter based on entropy change parameter. By establishing a relationship between entropy change and optimal charging current, the system adjusts current magnitude to match battery thermodynamic state, preventing excessive current that causes deterioration while maintaining efficient charging.
2Loss of time
If charging current is increased to reduce charging time, then loss of time is reduced, but harmful factors affecting battery increase
Solution Approach 1:
The system implements feedback control by measuring entropy change during charging and using this information to adjust charging current. The entropy change serves as a feedback signal that indicates battery state, allowing the controller to modulate current to prevent deterioration while maintaining charging efficiency.
Solution Approach 2:
The invention applies preliminary action by pre-establishing the relationship between entropy change and optimal charging current. Before actual charging occurs, the system determines the entropy-change-based current profile, allowing proactive adjustment rather than reactive response to deterioration signs.
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 effectively reduces battery deterioration by maintaining the charging current within permissible limits, balancing charging speed and battery life, as evidenced by reduced internal resistance increases.
Implementation Method 1
a non-aqueous electrolyte secondary battery (which is a lithium ion secondary battery)
Implementation Method 2
based on a relationship between the SOC of the battery and an entropy change of a battery reaction of the battery
Data Source
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AI summary
A method for charging a battery (2) that is a non-aqueous electrolyte secondary battery includes first and second steps. The first step is estimating an SOC of the battery (2) based on at least one of a voltage (VB) and a current (IB) of the battery (2). The second step is, based on a relationship between the SOC of the battery (2) and an entropy change ΔS, determining a maximum charging current (Imax) to the battery (2) in accordance with the SOC of the battery (2) such that the maximum charging current (Imax) becomes larger as the entropy change of the battery (2) becomes greater.