Lithium-Titanate Reference Electrode for Stable Li-Ion Cell Impedance Sensing
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Solution Overview
Problem
Conventional lithium-ion cells with reference electrodes made of lithium metal have low long-term stability and are not suitable for reliable impedance-spectroscopic measurements, which limits their ability to accurately determine the state of charge and aging.
Innovation Solution
A lithium-ion cell with a reference electrode made of lithium titanate powder, pressed onto the separator, enhancing stability and suitability for impedance spectroscopic measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium metal is used as the reference electrode, then the reference electrode can be implemented, but the long-term stability is low and it is not suitable for impedance-spectroscopic measurements
Solution Approach 1:
The patent changes the material parameter of the reference electrode from lithium metal to lithium titanate, which fundamentally alters the electrochemical properties. This material substitution provides both long-term stability and suitability for impedance-spectroscopic measurements, resolving the contradiction between reliability and measurement precision
Solution Approach 2:
The reference electrode is constructed as a composite structure consisting of lithium titanate particles embedded in a conductive matrix material. This composite design combines the stability of lithium titanate with the electrical conductivity of the matrix, achieving both long-term stability and measurement precision simultaneously
2Ease of manufacture
If lithium titanate powder is pressed to form the reference electrode, then production is simple and inexpensive, but the structural integrity must be maintained
Solution Approach 1:
The reference electrode utilizes a porous conductive matrix structure that allows lithium titanate particles to be embedded while maintaining structural integrity. The porous structure provides mechanical strength through the matrix framework while accommodating the powder particles, enabling simple pressing production without compromising strength
Solution Approach 2:
The composite structure of lithium titanate particles in a conductive matrix provides both ease of manufacture through simple pressing and adequate structural integrity. The matrix material binds the particles together, ensuring the pressed electrode maintains its form and function
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
The lithium titanate reference electrode ensures a long service life and reliable impedance-spectroscopic measurements, allowing for accurate determination of the cell's state of charge and aging.
Implementation Method 1
The separator arranged between the anode and cathode allows lithium ions to migrate freely through the electrolyte between the two electrodes
Data Source
AI summary
The invention relates to a lithium-ion cell (1) for an energy storage unit of a motor vehicle, having at least one anode (3), at least one cathode (4), an electrolyte and a separator (7) arranged between the cathode (4) and anode (3) in the electrolyte, and having a reference electrode (8) for determining a voltage potential of the lithium-ion cell (1). The reference electrode (8) is produced from lithium titanate.