EV Charging Control for SOH Estimation and Polarization Delay
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Solution Overview
Problem
Existing charging technologies inaccurately estimate the State of Health (SOH) of secondary batteries due to insufficient or absent standby time for polarization elimination, leading to potential undercharging or inaccurate estimation.
Innovation Solution
A charging control device that includes a processor to estimate SOH by integrating charging power and using an SOC-OCV characteristic curve, with separate charging controls for home and non-home environments to ensure accurate estimation and prevent undercharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standby time is provided for elimination of polarization, then the SOH estimation accuracy is improved, but the charging time is extended and the battery may not be charged sufficiently
Solution Approach 1:
The patent applies dynamics by making the pre-charging standby time flexible rather than fixed. The control device dynamically adjusts the standby time duration based on real-time battery state measurements (voltage, temperature, SOC) and polarization elimination rate. This allows the system to adapt the waiting period to actual battery conditions, achieving accurate SOH estimation without unnecessarily extending charging time.
Solution Approach 2:
The patent implements feedback control by continuously monitoring battery voltage, temperature, and state of charge during the pre-charging phase. The control device uses this feedback information to determine when polarization has sufficiently eliminated, allowing the system to proceed to active charging. This feedback mechanism ensures accurate SOH estimation while minimizing idle standby time.
2Productivity
If no standby time is provided for elimination of polarization, then the charging time is reduced, but the SOH estimation becomes inaccurate
Solution Approach 1:
The patent applies preliminary action by implementing a pre-charging phase before active charging begins. During this phase, the control device allows the battery to rest and eliminates polarization through controlled small-current charging or open-circuit resting. This preliminary preparation ensures that subsequent SOH estimation based on OCV measurements will be accurate, while the duration is optimized to minimize total charging time.
Solution Approach 2:
The patent changes parameters dynamically during the pre-charging phase, adjusting voltage, current, and time parameters based on real-time battery state. The control device modifies these parameters to optimize the balance between polarization elimination and time consumption, enabling efficient preparation for accurate SOH estimation without excessive waiting time.
3Measurement precision
If a fixed pre-charging standby time is applied to all charging scenarios, then the SOH estimation is accurate for home charging, but insufficient charging occurs at other locations
Solution Approach 1:
The patent makes the pre-charging standby time dynamic and adaptive to different charging scenarios. The control device adjusts the standby time duration based on location type (home vs. other locations), battery state, and user preferences. This dynamic adaptation allows the system to maintain accurate SOH estimation at home while providing faster charging at other locations where time is more constrained.
Solution Approach 2:
The patent applies local quality by implementing different pre-charging strategies for different locations. At home locations, a longer pre-charging standby time is applied to ensure accurate SOH estimation. At other locations, a shorter or optimized pre-charging phase is used to prioritize charging speed. This location-specific approach optimizes performance for each charging scenario.
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
Accurately estimates SOH by providing standby times for polarization elimination at home and allowing immediate charging elsewhere, preventing undercharging and ensuring precise SOH calculation.
Implementation Method 1
the SOC (State Of Charge) of the battery is calculated using an OCV (Open Circuit Voltage) when polarization occurring after charging of the battery is eliminated
Implementation Method 2
a predetermined pre-charging standby time based on a time required for elimination of polarization of the secondary battery
Data Source
AI summary
When charging is performed at home of a user of a vehicle, a processor performs first charging control to start the charging after an elapse of a standby time based on a time required for elimination of polarization of a battery pack and, when the charging is performed at a place other than the home, the processor performs second charging control to start the charging before the elapse of the standby time. The processor performs control to estimate the SOH, after each of the first charging control and the second charging control.