Real-Time Lithium Plating Detection via dV/dQ Analysis
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Solution Overview
Problem
Current methods fail to detect lithium plating in lithium ion secondary batteries in real time, particularly in actual use environments, leading to capacity loss and safety issues due to side reactions and degradation.
Innovation Solution
A method that monitors battery voltage as a function of State of Charge (SOC) during charging to identify the lithium plating occurrence point by analyzing the SOC-dV/dQ graph, allowing for stepwise adjustment of charge rates to prevent lithium plating, and includes a system with sensors and a controller to implement this protocol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional detection methods (heat capacity analysis, thickness increase analysis) are used, then lithium plating can be detected, but they cannot measure in actual use environment and require destructive testing
Solution Approach 1:
The patent replaces destructive mechanical analysis methods (heat capacity analysis, thickness increase analysis) with an electrical measurement method. By monitoring battery voltage changes during charging and calculating dV/dQ, the system detects lithium plating through electrical signals without requiring destructive disassembly or specialized equipment, enabling detection in actual use environments.
Solution Approach 2:
The patent utilizes the battery's own voltage characteristics during normal charging operation to detect lithium plating. The method requires no external testing equipment or disruption of normal battery function - the battery serves its own detection purpose through its inherent voltage response to plating conditions, allowing simultaneous operation and detection.
2Productivity
If high charge rates are applied, then charging speed increases, but lithium plating occurs on the negative electrode surface
Solution Approach 1:
The patent implements a feedback control system that continuously monitors battery voltage during charging, calculates dV/dQ in real-time, and compares it against threshold values. When lithium plating is detected (dV/dQ exceeds threshold), the system automatically adjusts charging parameters or stops charging, creating a closed-loop control that prevents plating while maximizing charging speed under safe conditions.
Solution Approach 2:
The patent employs dynamic charging rate adjustment based on real-time detection of lithium plating conditions. Rather than using a fixed charge rate, the system continuously adapts the charging current based on the detected dV/dQ values, allowing high charge rates when safe and reducing or stopping when plating risk is detected, optimizing both speed and safety throughout the charging process.
Data Source
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AI summary
Provided is a non-destructive method for detecting lithium plating by which lithium plating can be detected in real time in an actual use environment of a secondary battery, a secondary battery charging method and apparatus for charging a secondary battery under the condition in which lithium plating does not occur by using this method, and a secondary battery system for detecting the state of a secondary battery by using this method. The method for detecting lithium plating according to the present disclosure is a method which detects lithium plating in a negative electrode in real time by observing a change in battery voltage as a function of SOC during charging a secondary battery, and determines a point at which a rise speed of the battery voltage slows down as a lithium plating occurrence point.