Solid-State Battery Short-Circuit Prediction via Dual Resistance Monitoring

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Solution Overview

Problem

Conventional methods fail to predict internal short circuits in all-solid-state lithium secondary batteries due to lithium dendrite formation before the short circuit occurs.

Innovation Solution

A system that calculates electrolyte and reaction resistances from AC impedance measurements, predicting a possible internal short circuit by monitoring the change rate of electrolyte resistance and reaction resistance values within predetermined ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional state detection methods are used to monitor battery status, then general battery deterioration can be detected, but internal short circuits due to lithium dendrites cannot be predicted before they occur

Engineering Contradiction:

Improveshort circuit prediction accuracyVSAvoiddendrite detection capability

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the measurement parameters from conventional single impedance measurement to dual-parameter monitoring (electrolyte resistance and reaction resistance). By specifically monitoring these two resistance parameters and their rates of change, the system can detect dendrite formation before it causes short circuits, thereby improving prediction accuracy while maintaining measurement feasibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces conventional mechanical/electrical state detection methods with electrochemical impedance spectroscopy (EIS) based detection. By using AC impedance measurements and analyzing the resulting resistance parameters, the system achieves non-invasive detection of dendrite formation, enabling early warning before short circuits occur

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If AC impedance measurement is performed to calculate electrolyte resistance and reaction resistance, then internal short circuit can be predicted, but measurement time and system complexity increase

Engineering Contradiction:

Improveshort circuit prediction capabilityVSAvoidmeasurement time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary AC impedance measurements during normal battery operation to establish baseline electrolyte resistance and reaction resistance values. By continuously monitoring these parameters and their rates of change, the system can predict short circuits without requiring extensive measurement time at critical moments, thus improving reliability while minimizing time loss

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes the battery's own electrical characteristics during normal operation to perform self-diagnosis through impedance measurement. The battery's inherent electrochemical responses provide the measurement signals needed, eliminating the need for external testing equipment or disassembly, thereby reducing measurement time and system complexity

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables the prediction of internal short circuits before they occur, allowing for preventive measures to be taken and extending the battery's operational lifespan.

Implementation Method 1

measuring an AC impedance of the secondary battery (S2)

Methodology Applied

Scientific EffectAC impedance measurement: Electrical Resistance

Implementation Method 2

calculating an electrolyte resistance and a reaction resistance of the secondary battery (S2) from the AC impedance

Methodology Applied

Scientific EffectElectrochemical impedance analysis: Electrical Resistance

Data Source

PatentEP4016096B1Secondary battery short-circuiting assessment device, short-circuiting assessment method, and short-circuiting assessment system

Publication Date: 2023.06.07 NISSAN MOTOR CO LTD

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AI summary

A short-circuit prediction device for predicting the presence or absence of occurrence of an internal short circuit in a secondary battery (2) is provided. The secondary battery (2) has a positive electrode, a solid electrolyte, and a negative electrode that contains a lithium alloy. The short-circuit prediction device includes a measurement instrument (7) that measures AC impedance of the secondary battery (2) and a controller (8) that predicts the internal short circuit in the secondary battery (2). The measurement instrument (7) calculates electrolyte resistance of the secondary battery (2) and reaction resistance of the secondary battery (2) from the AC impedance. When a change rate of the electrolyte resistance per a predetermined period is within a predetermined range and the reaction resistance becomes higher than a predetermined upper limit, the controller (8) predicts that there is a possibility of occurrence of the internal short circuit.