All-solid-state Battery Ion Pathway Interruption Detection
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Solution Overview
Problem
All-solid-state batteries with lithium metal as the negative electrode active material face ion pathway interruptions due to partial defects at the interface between the negative electrode and solid electrolyte, leading to decreased output, which is difficult to detect and manage.
Innovation Solution
A battery system with a voltage detection device, current detection device, and control device that calculates changes in charging parameters to detect ion pathway interruptions by comparing integrated current and voltage values, allowing for abnormality judgment and output restriction when such interruptions occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as the negative electrode active material to enhance energy density, then energy density is improved, but ion pathway interruptions occur due to partial defects at the interface, leading to decreased reliability
Solution Approach 1:
The patent applies preliminary action by calculating the state of charge (SOC) based on open circuit voltage (OCV) before comparing it with current-integration-based SOC. This pre-calculation allows the system to detect discrepancies that indicate ion pathway interruptions before they significantly degrade battery performance, enabling preventive management of the reliability issue while maintaining high energy density from lithium metal usage
2Power
If high current discharge is used to increase output, then power is improved, but local dissolution of lithium metal progresses considerably, causing partial defects and ion pathway interruptions
Solution Approach 1:
The patent implements feedback by continuously monitoring and comparing two different SOC calculation methods: one based on current integration and another based on OCV measurement. When discrepancies exceed a threshold, the system detects ion pathway interruptions and can adjust discharge rates accordingly, providing feedback control that manages reliability while allowing high power output when conditions are favorable
3Device complexity
If conventional SOC calculation methods are used, then device complexity is kept low, but ion pathway interruptions cannot be detected, leading to loss of information about battery health
Solution Approach 1:
The patent uses feedback by implementing a comparison mechanism between two SOC calculation approaches. The control unit calculates SOC through current integration and separately through OCV measurement, then compares these values. This feedback loop provides information about battery health status without requiring complex additional hardware, detecting ion pathway interruptions through intelligent processing of existing measurements
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 early detection and management of ion pathway interruptions, preventing further degradation and maintaining battery performance by restricting output when abnormalities are detected.
Implementation Method 1
a solid electrolyte layer which contains lithium ion and has lithium ion conductivity; conduction of lithium ions through the solid electrolyte layer
Implementation Method 2
deposition and dissolution of lithium metal are repeated in the negative electrode active material layer
Data Source
AI summary
A battery system 5 is provided with an all-solid-state battery 10, a voltage detection device that detects voltage of the all-solid-state battery, a current detection device 66 that detects current flowing from the all-solid-state battery, and a control device 50 that controls the all-solid-state battery. A negative electrode active material layer is composed of lithium metal. The control device calculates the amount of change in charging rate as a first estimated value, based on an integrated value obtained by integrating detected current over a prescribed calculation period, calculates the amount of change in charging rate as a second estimated value, based on voltage detected during the calculation period as a second estimated value, and judges that an abnormality has occurred in the all-solid-state battery when the difference between the first estimated value and the second estimated value is equal to or greater than a predetermined reference value.