Battery Cell Resistance Diagnosis Using Reference Voltage Ranges

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Solution Overview

Problem

The capacity retention rate behavior and resistance increase rate behavior of unit cells with high-manganese positive electrode materials do not match in the entire voltage range, making it difficult to predict the degree of aging accurately.

Innovation Solution

An apparatus and method that determine a reference voltage range based on the discharge profile of a unit cell, allowing for accurate diagnosis of the resistance increase rate by identifying the capacity retention rate within this range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the entire voltage range is used for diagnosis, then more data is available for analysis, but the capacity retention rate behavior and resistance increase rate behavior do not match, reducing prediction accuracy

Engineering Contradiction:

Improvedata availabilityVSAvoidprediction accuracy

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

The voltage range is segmented into multiple sub-ranges, and a reference voltage range is selected where the capacity retention rate behavior and resistance increase rate behavior match. This segmentation allows the system to use only the portion of data that provides accurate prediction, rather than using the entire voltage range.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of treating the entire voltage range uniformly, the patent identifies specific local regions (voltage sub-ranges) where the diagnostic parameters exhibit matching behavior. The diagnosis is then performed using data from these specific local regions where the quality of correlation between capacity retention and resistance increase is high.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If a reference voltage range is determined to improve prediction accuracy, then aging prediction becomes more precise, but the diagnostic process becomes more complex

Engineering Contradiction:

Improveaging prediction precisionVSAvoiddiagnostic process complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The reference voltage range is determined in advance through preliminary analysis of the discharge profile. By pre-identifying the voltage range where capacity retention rate and resistance increase rate match, the system avoids the need for complex real-time analysis during actual diagnosis, thereby reducing operational complexity while maintaining high prediction accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses the discharge profile data, which is already available from normal battery operation, as a basis for determining the reference voltage range. This approach leverages existing data rather than requiring additional expensive or complex measurement systems, achieving accurate diagnosis through intelligent processing of readily available information.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP4707829A1Resistance increase rate diagnosis device and operation method thereof

Publication Date: 2026.03.11 LG ENERGY SOLUTION LTD

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AI summary

An apparatus for diagnosing resistance increase rate of cellaccording one embodiment of thepresent disclosure may include: a determination unit that determines a reference voltage range based on a discharge profile of a unit cell, an identification unit that identifies a capacity retention rate in a reference voltage range of a unit cell subjected to a specified number of charge-discharge cycles, and a diagnosis unit that diagnoses a resistance increase rate of the unit cell based on the identified capacity retention rate.