Battery Fast Charging with Initial SOC Compensation Current
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Solution Overview
Problem
Conventional quick charging technology for lithium secondary batteries does not consider the initial state of charge (SOC) of the battery, leading to inefficient charging when the SOC exceeds the lowest section, despite the capability to use higher currents without lithium plating.
Innovation Solution
A method and apparatus that calculate the initial charge current by combining a quick charge map and a compensation current map, considering both the SOC and initial charge state to determine a total charge current that includes a compensation current, thereby overcoming the limitations of conventional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional quick charge map is used without considering initial SOC, then charging process is simplified, but charging efficiency decreases when initial SOC exceeds lowest section
Solution Approach 1:
The patent segments the charging control into two distinct maps: a quick charge map for determining base charge current based on temperature and real-time SOC, and a compensation current map for adding initial SOC-based compensation current. This segmentation allows each map to handle specific aspects of charging control independently, resolving the contradiction by maintaining simplicity in individual maps while achieving high efficiency through their combination.
Solution Approach 2:
The patent merges the quick charge map and compensation current map together to form a comprehensive charging control system. The final charge current is calculated by combining the quick charge current from the quick charge map with the compensation current from the compensation current map. This merging enables the system to achieve high charging efficiency by utilizing higher currents when initial SOC is low, while maintaining manageable complexity through the modular structure of the two maps.
2Speed
If higher charge current is applied when initial SOC is high, then charging speed increases, but lithium plating risk increases
Solution Approach 1:
The patent changes the charge current parameter dynamically based on initial SOC conditions. When initial SOC is low, the compensation current map allows higher charge currents to be applied safely. When initial SOC is high, the compensation current is reduced or eliminated, preventing lithium plating. This parameter change strategy resolves the contradiction by adaptively adjusting charge current according to battery state, enabling high charging speed when safe and preventing lithium plating when risk exists.
3Reliability
If charge current is limited by conventional quick charge map, then lithium plating is prevented, but charging time increases
Solution Approach 1:
The patent performs preliminary assessment of initial SOC before charging begins and pre-calculates the appropriate compensation current from the compensation current map. This preliminary action enables the system to apply higher charge currents from the start when initial SOC is low, reducing overall charging time while maintaining lithium plating prevention through the pre-planned compensation current strategy.
Solution Approach 2:
The patent implements feedback by continuously monitoring real-time SOC and comparing it with initial SOC, then adjusting the charge current accordingly. The compensation current map provides feedback-based current adjustments that allow higher currents when initial SOC is low (reducing charging time) while preventing lithium plating when initial SOC is high. This feedback mechanism resolves the contradiction by dynamically optimizing charge current based on battery state changes during charging.
Data Source
AI summary
The apparatus and method for fast charging of battery according to aspects of the disclosure may add a compensation current considering the current gain according to initial state of charge of the battery to the existing charge current of the battery obtained by considering only the temperature and real-time state of charge of the battery and supply it to the battery, thereby shortening fast charging time.