Battery Cell Diagnosis for Lithium Plating and Tab Disconnection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Batteries can ignite due to internal short-circuits caused by lithium precipitation on the negative electrode, which is exacerbated by repetitive charging, posing a risk of thermal runaway.
Innovation Solution
A battery diagnosis apparatus that diagnoses lithium precipitation and negative electrode tab disconnection by analyzing battery voltage deviations and cumulative deviations, using threshold values and rates to identify abnormal cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If battery cells are repeatedly charged to increase energy storage capacity, then energy density and productivity are improved, but lithium precipitation occurs on the negative electrode causing internal short-circuits and thermal runaway
Solution Approach 1:
The patent performs preliminary diagnosis actions by calculating voltage deviations and cumulative deviations during rest periods before thermal runaway occurs. The system identifies abnormal battery cells through voltage deviation analysis and accumulative summation, enabling early detection and prevention of lithium precipitation and internal short-circuits, thus maintaining reliability while allowing continuous charging cycles for high productivity
2Measurement precision
If voltage deviation analysis is performed to detect abnormal battery cells, then measurement precision for detecting lithium precipitation is improved, but device complexity increases due to additional calculation units and algorithms
Solution Approach 1:
The patent segments the battery module into multiple cell groups connected in parallel, where each cell group contains multiple battery cells. The diagnosis system independently calculates voltage deviations for each cell group and performs accumulative summation separately. This segmentation enables precise detection of abnormal cells through comparative analysis while distributing the computational load, thereby improving measurement precision without proportionally increasing device complexity
Solution Approach 2:
The patent introduces voltage deviation and cumulative deviation as intermediary parameters to detect abnormal battery cells. Instead of directly measuring lithium precipitation or internal short-circuits, the system uses voltage deviations during rest periods as intermediate indicators. The accumulative deviation serves as a mediator that amplifies small voltage differences over time, enabling high-precision detection while avoiding complex direct measurement of the actual defects
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A battery diagnosis apparatus according to an embodiment disclosed herein includes an obtaining unit configured to obtain voltage data in a rest period of a plurality of battery cells included in a battery module, a deviation calculating unit configured to calculate a voltage deviation between adjacent periods at designated time intervals from a designated point in time, in the unit of cell groups connected in parallel to each other among the plurality of battery cells, based on the voltage data, a cumulative calculating unit configured to calculate a cumulative deviation by cumulatively summing the voltage deviation in the unit of cell group, when a maximum voltage deviation among a plurality of voltage deviations of a plurality of cell groups in a target period is greater than or equal to a first threshold value, and a diagnosing unit configured to diagnose, as abnormal battery cells, battery cells included in a cell group which satisfies designated conditions among the plurality of cell groups, based on the voltage deviation and the cumulative deviation.