Battery Differential-Profile Curvature for Lithium Plating Detection
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Solution Overview
Problem
Existing battery monitoring technologies face challenges in accurately detecting lithium precipitation in batteries, particularly in electric vehicles, which can lead to internal short circuits and potential fires, without causing destructive damage to the battery.
Innovation Solution
A battery monitoring apparatus and method that calculates the curvature of the differential voltage profile relative to the state of charge (SOC) of the battery, compares it to a preset threshold, and determines lithium precipitation based on this comparison, allowing for non-destructive monitoring and diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional battery monitoring methods are used, then the monitoring process is simple, but the detection accuracy of lithium precipitation is insufficient
Solution Approach 1:
The patent transforms the monitoring approach by changing the parameter being measured from direct voltage to differential voltage (dV/dSOC), and further to the curvature of the differential voltage profile. This parameter transformation enables detection of lithium precipitation through subtle changes in the voltage-SOC relationship that are not visible in conventional voltage measurements, thereby improving detection accuracy while maintaining reasonable system complexity
Solution Approach 2:
The system performs preliminary calculations to generate the differential voltage profile and compute curvature values before actual lithium precipitation occurs. By establishing baseline curvature characteristics and threshold values in advance, the system can detect lithium precipitation through simple comparison operations, improving both detection accuracy and operational efficiency
2Measurement precision
If destructive testing methods are used to detect lithium precipitation, then detection accuracy improves, but battery damage occurs
Solution Approach 1:
The patent replaces physical-destructive testing methods with an electrical measurement-based approach. By measuring voltage characteristics and computing differential profiles during normal battery operation, the system can detect lithium precipitation without applying mechanical stress, thermal shock, or other damaging interventions, thus achieving accurate detection while preserving battery integrity
Solution Approach 2:
The system introduces differential voltage as an intermediary parameter that indirectly indicates lithium precipitation. Instead of directly observing physical changes that would require destructive testing, the method uses the intermediary relationship between voltage-SOC characteristics and lithium deposition to enable non-destructive detection through electrical measurements
Data Source
AI summary
An apparatus for diagnosing a state of a battery includes a profile generating unit configured to generate a differential profile representing a corresponding relationship between a differential voltage representing a change rate of a voltage of a battery to a SOC of the battery and the SOC; and a control unit configured to calculate a curvature corresponding to a preset SOC region in the differential profile, compare the calculated curvature with a preset criterion curvature for the battery, and judge whether lithium is precipitated in the battery based on the comparison result.