Hybrid Battery Anode Cycle-Life Prediction from d-Spacing Slopes
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Solution Overview
Problem
Current secondary batteries with non-carbon based negative electrodes, such as silicon, face challenges in cycle life due to volume expansion leading to cracks and reduced electrical contact, limiting the improvement in cycle life when mixed with carbon-based materials.
Innovation Solution
A method to predict the cycle life of a carbon-based hybrid negative electrode by measuring lattice d-spacing changes during charging/discharging using an X-ray diffractometer, calculating slope differences, and comparing these to a reference battery to determine if the cycle life is improved or degraded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If non-carbon based materials (e.g., silicon) are used as negative electrode active material to achieve high theoretical capacity, then capacity is improved, but cracks and splitting failures occur due to high volume expansion rate during alloying with lithium, resulting in reduced cycle life
Solution Approach 1:
The patent applies composite materials by combining non-carbon based materials (such as silicon) with carbon based materials to form a hybrid negative electrode. This composite structure allows the non-carbon material to provide high theoretical capacity while the carbon material constrains volume expansion and prevents cracks, thereby maintaining both high capacity and long cycle life
2Reliability
If a hybrid negative electrode comprising a mixture of non-carbon based materials and carbon based materials is applied to solve the problem of volume expansion, then cycle life is improved, but simply mixing the materials still has limitations in further improving cycle life
Solution Approach 1:
The patent applies local quality by designing a specific structural arrangement where non-carbon based materials are dispersed within a carbon based matrix rather than simple mixing. This localized configuration ensures that the carbon material provides structural support exactly where volume expansion occurs, optimizing the cycle life improvement efficiency
Solution Approach 2:
The patent applies parameter changes by optimizing the ratio of non-carbon based materials to carbon based materials in the hybrid negative electrode. By adjusting this compositional parameter, the patent achieves maximum cycle life improvement while maintaining high capacity, overcoming the limitations of simple mixing
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 cycle life improvement by analyzing the singular and combined behaviors of carbon and non-carbon based materials, allowing for the optimization of hybrid negative electrodes in secondary batteries.
Implementation Method 1
measuring a lattice d-spacing of a carbon based negative electrode active material of a target carbon-based hybrid negative electrode using an X-ray diffractometer
Data Source
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AI summary
Disclosed is a method of predicting cycle life of a secondary battery comprising a carbon-based hybrid negative electrode, comprising: measuring a lattice d-spacing of a carbon based negative electrode active material of a target carbon-based hybrid negative electrode using an X-ray diffractometer during charging/discharging of a target secondary battery comprising the target carbon-based hybrid negative electrode comprising a carbon based negative electrode active material and a non-carbon based negative electrode active material, and plotting a graph of changes in lattice d-spacing value as a function of charge/discharge capacity (X axis); calculating a target slope difference corresponding to a difference in slope value changed with respect to an inflection point of the graph during discharging in the plotted graph; comparing the target slope difference with a reference slope difference corresponding to a difference in the slope value changed with respect to an inflection point in a graph showing changes in lattice d-spacing value as a function of charge/discharge capacity (X axis) of a reference secondary battery; and predicting if the cycle life of the target secondary battery is improved compared to the reference secondary battery from a result of the comparison.