Mesh-Anode Secondary Battery for Silicon Expansion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of silicon, tin, or aluminum as negative electrode active materials in secondary batteries leads to significant expansion and contraction during charging and discharging, causing micronization and loss of the active material, resulting in decreased discharge capacity.
Innovation Solution
A secondary battery design with separate positive and negative electrode electrolytic solution filling parts, each containing a conductive member with a mesh structure to retain the active material, allowing it to function despite micronization, and using electrolytic solutions tailored to each electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon, tin, or aluminum is used as negative electrode active material to achieve high capacity, then the discharge capacity is improved, but the active material undergoes micronization and loss due to large expansion and contraction during charging and discharging
Solution Approach 1:
The invention employs a flexible gel electrolyte layer that can accommodate the large expansion and contraction of silicon, tin, or aluminum-based negative electrode active materials during charging and discharging cycles. The gel electrolyte's viscoelastic properties allow it to maintain continuous ionic contact with the active material particles even when they undergo significant volume changes, preventing particle isolation and maintaining electrochemical activity throughout the battery's operational life.
Solution Approach 2:
The invention changes the physical state of the electrolyte from liquid to gel form, fundamentally altering its mechanical properties. This parameter change enables the electrolyte to provide both ionic conductivity and mechanical support, allowing it to withstand and accommodate the large dimensional changes of high-capacity negative electrode materials without losing electrical contact or allowing active material loss.
2Device complexity
If a single common electrolytic solution is used for both positive and negative electrodes to simplify the battery structure, then the device complexity is reduced, but the performance of both electrodes cannot be optimized simultaneously
Solution Approach 1:
The invention segments the electrolytic solution into two distinct gel electrolyte layers: a positive electrode gel electrolyte layer in contact with the positive electrode, and a negative electrode gel electrolyte layer in contact with the negative electrode. This segmentation allows each electrolyte layer to be independently optimized for its respective electrode's chemical and electrical characteristics, enabling simultaneous performance optimization of both electrodes while maintaining a relatively simple overall battery structure.
Solution Approach 2:
The invention applies the principle of local quality by providing different electrolyte compositions tailored to the specific requirements of each electrode. The positive electrode gel electrolyte can be formulated with additives and solvents optimized for lithium cobalt oxide or lithium manganese oxide, while the negative electrode gel electrolyte can be optimized for graphite or silicon-based anodes, thereby maximizing the electrochemical performance of each electrode locally.
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 suppresses the decrease in discharge capacity by capturing micronized active materials and improves battery performance by using electrolytes optimized for each electrode.
Implementation Method 1
a non-aqueous solvent dissolving the electrolyte salt
Implementation Method 2
an electrolyte layer disposed between the positive electrode current collector and the negative electrode current collector
Implementation Method 3
a conductive member having a mesh structure and disposed so as to bring the negative electrode current collector and the electrolyte layer into conduction; a negative electrode active material retained in the conductive member
Implementation Method 4
expansion and contraction of the negative electrode active material attributable to charging and discharging of the secondary battery
Data Source
Figure 1
Figure 2(a)~2(b)
AI summary
Disclosed is a secondary battery comprising: a positive electrode current collector; a negative electrode current collector; an electrolyte layer disposed between the positive electrode current collector and the negative electrode current collector; a positive electrode electrolytic solution filling part partitioned by the positive electrode current collector and the electrolyte layer; and a negative electrode electrolytic solution filling part partitioned by the negative electrode current collector and the electrolyte layer. The negative electrode electrolytic solution filling part comprises: a conductive member having a mesh structure and disposed so as to bring the negative electrode current collector and the electrolyte layer into conduction; a negative electrode active material retained in the conductive member; an electrolyte salt; and a non-aqueous solvent dissolving the electrolyte salt. The negative electrode active material comprises at least one selected from the group consisting of silicon, tin, and aluminum, as a constituent element.