Secondary Battery Step Charging Using Polarization Voltage Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional step charging methods for secondary batteries do not adequately consider the polarization state of the battery before charging, leading to inefficient charging times and potential lithium precipitation issues.
Innovation Solution
An apparatus and method that adaptively adjusts the charging current based on the state of charge (SOC) and polarization voltage of the secondary battery using a voltage, current, and temperature measuring units, along with a charging control unit that employs an extended Kalman filter to estimate SOC and polarization voltage, allowing for dynamic control of the charging current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional step charging method is used with fixed SOC regions, then charging current magnitude is maintained constant in each region, but charging time is extended and lithium precipitation may occur due to inadequate consideration of polarization state
Solution Approach 1:
The patent dynamically adjusts charging current magnitude by considering both SOC and polarization voltage state. Instead of using fixed SOC regions with constant current, the system continuously monitors polarization voltage and adapts the charging current in real-time, allowing for optimized charging speed while preventing lithium precipitation through responsive current adjustment.
Solution Approach 2:
The patent changes the control parameters from solely SOC-based to a combined SOC and polarization voltage-based system. By introducing polarization voltage as an additional control parameter, the system can more accurately determine the appropriate charging current magnitude, preventing lithium precipitation while reducing charging time through optimized current profiles.
2Productivity
If charging current magnitude is increased to shorten charging time, then charging speed improves, but risk of lithium precipitation increases
Solution Approach 1:
The patent implements a feedback mechanism that continuously monitors polarization voltage and uses this information to adjust charging current magnitude. The polarization voltage serves as a feedback signal indicating the battery's readiness to accept higher current, allowing the system to increase charging speed when safe and reduce current when lithium precipitation risk arises.
Solution Approach 2:
The patent performs preliminary assessment of polarization voltage before determining charging current magnitude. By evaluating the polarization state in advance, the system can proactively set appropriate current levels that maximize charging speed while preemptively preventing lithium precipitation conditions.
3Loss of time
If step charging control is optimized based on polarization voltage, then charging time is shortened, but measurement and control complexity increases
Solution Approach 1:
The patent uses the existing voltage measuring unit to serve dual purposes: measuring terminal voltage for SOC calculation and measuring polarization voltage for current control optimization. This multi-functionality approach avoids adding separate measurement hardware, reducing the complexity increase while enabling polarization-based charging optimization.
Data Source
AI summary
A computer device includes a non-transitory storage medium configured to store a plurality of processor executive commands and a processor configured to execute the plurality of processor executive commands. By executing the processor executive commands, the processor may be configured to estimate a state of charge (SOC) based on at least one of a measured voltage value, a measured current value, and a measured temperature value, correct the estimated SOC based on a polarization voltage of a secondary battery, determine a magnitude of a charging current based on the corrected SOC and the measured temperature value, and provide information on the determined magnitude of the charging current to a charging device.