Lithium Ion Battery Anode Composite for Volume Expansion
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Solution Overview
Problem
Existing lithium ion secondary batteries face significant capacity deterioration and volume expansion issues when using silicon oxide as an anode active material, particularly at elevated temperatures, due to insufficient understanding of the interactions between anode components, binders, electrolytic solutions, and electrode structures.
Innovation Solution
A lithium ion secondary battery design featuring a planar stacking structure with an anode composed of carbon, metal, and metal oxide, where the metal oxide has an amorphous structure and the metal is dispersed within it, along with a specific electrolytic solution that prevents carbon dioxide generation, enhancing electroconductivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon oxide is used as an anode active material to achieve high energy density, then capacity is improved, but capacity deterioration becomes significantly large at 45°C or higher
Solution Approach 1:
The patent uses a composite anode structure containing silicon oxide particles dispersed in a carbon matrix, where the carbon material provides structural stability and prevents excessive volume expansion while the silicon oxide provides high capacity. This composite approach resolves the contradiction by combining the high energy density of silicon oxide with the dimensional stability of carbon.
Solution Approach 2:
The patent modifies the particle size parameters of silicon oxide (controlling average diameter and distribution) and the carbon matrix structure to optimize performance. By controlling the size and morphology parameters, the anode achieves both high capacity and improved cycle stability at elevated temperatures.
2Quantity of substance
If silicon oxide is used as an anode active material, then capacity is improved, but volume expansion occurs during charge/discharge cycles
Solution Approach 1:
The patent embeds silicon oxide particles within a carbon matrix composite structure. The carbon material accommodates the volume expansion of silicon oxide during lithium insertion while maintaining overall structural integrity, thus preventing excessive anode volume change and preserving electrode morphology during cycling.
Solution Approach 2:
The carbon matrix acts as a flexible shell surrounding the silicon oxide particles, providing a buffer that absorbs volume expansion stress during charge/discharge cycles while maintaining the structural framework of the anode.
3Reliability
If conventional electrolytic solutions are used with silicon oxide anode, then electroconductivity is maintained, but carbon dioxide is generated through reductive decomposition
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolytic solution by incorporating fluorinated cyclic carbonate components, which have higher decomposition potentials and form more stable solid electrolyte interface (SEI) films. This change reduces carbon dioxide generation while maintaining adequate ionic conductivity for battery operation.
4Ease of manufacture
If anode components, binders, and electrolytic solutions are not optimized together, then manufacturing is simpler, but capacity deterioration and volume expansion occur
Solution Approach 1:
The patent employs a polyimide binder that performs multiple functions: it provides mechanical adhesion between anode particles, maintains electrode structural integrity during volume changes, and contributes to electrochemical stability. This multi-functional approach simplifies the overall system while improving reliability.
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 design achieves long-life operation with improved energy density and cycle life by minimizing volume expansion and electrolyte decomposition, while maintaining structural integrity and preventing gas accumulation between electrodes.
Implementation Method 1
carbon material (a) that can absorb and desorb a lithium ion
Implementation Method 2
metal (b) that can be alloyed with lithium
Implementation Method 3
an electrolytic solution are enclosed inside an outer packaging body
Data Source
Figure 1
AI summary
An exemplary embodiment provides a lithium ion secondary battery using a high energy type anode, which enables long-life operation thereof. A secondary battery according to an exemplary embodiment comprises an electrode element in which a cathode and an anode are oppositely disposed, an electrolytic solution, and an outer packaging body which encloses the electrode element and the electrolytic solution inside; wherein the anode is formed by binding an anode active material, which comprises carbon material (a) that can absorb and desorb a lithium ion, metal (b) that can be alloyed with lithium, and metal oxide (c) that can absorb and desorb a lithium ion, to an anode collector with an anode binder; and wherein the electrolytic solution comprises a liquid medium which is hard to generate carbon dioxide at a concentration of 10 to 80 vol%.