Porous Anode Wire for Cable Battery Stress Relief
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Solution Overview
Problem
Cable-type secondary batteries face issues with deformation and performance deterioration due to external physical impact and internal stress caused by repeated charge and discharge, particularly when using anode active materials like Si or Sn, leading to disconnection and reduced stability.
Innovation Solution
A porous anode for lithium secondary batteries is developed, featuring a wire current collector with a porous shell of 10-150 µm pore size, made from materials like Si, Sn, or oxides, which provides cushioning and increased surface area for improved lithium ion mobility, using a method involving electroplating or anodic oxidation to form the porous shell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a cable-type secondary battery is designed with high flexibility and linear shape, then it can be easily adapted in shape and reduce assembly space, but it becomes prone to deformation and disconnection due to external physical impact
Solution Approach 1:
The patent introduces a buffer layer between the electrode assembly and the outer casing that provides beforehand cushioning against external physical impacts. This buffer layer absorbs and distributes impact forces before they reach the fragile electrode assembly, preventing deformation and disconnection while maintaining the cable-type battery's flexible adaptability
2Power
If an anode active material such as Si or Sn is used, then electrochemical reactivity is improved, but the anode active material separates during repeated charge and discharge causing performance deterioration
Solution Approach 1:
The patent employs a flexible buffer layer that can expand and contract dynamically during charge-discharge cycles. This flexible structure accommodates the volume changes of high-capacity anode materials like Si or Sn without causing mechanical separation, maintaining both electrochemical reactivity and structural stability
Solution Approach 2:
The patent changes the physical parameters of the buffer layer (porosity, thickness, material composition) to optimize its cushioning effect. By adjusting these parameters, the buffer layer can effectively absorb expansion forces during lithiation and maintain structural integrity during delithiation, preventing active material separation
3Duration of action of moving object
If electrodes are expanded and contracted during repeated charge and discharge, then electrochemical function is achieved, but internal stress increases causing anode active material separation
Solution Approach 1:
The buffer layer acts as an intermediary between the electrode assembly and the rigid outer casing. It mediates the stress transmission by absorbing expansion forces during charge-discharge cycles, preventing direct stress transfer that would cause active material separation while allowing continuous electrochemical cycling
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 porous anode enhances resistance to physical impact, relieves internal stress, and maintains battery stability by preventing deformation and improving ionic conductivity, resulting in superior battery performance.
Implementation Method 1
the shell is porous and has a pore size of 10 to 150 μm... exhibits high electrochemical reactivity and is capable of relieving internal stress and pressure of the battery
Implementation Method 2
using a method involving electroplating or anodic oxidation to form the porous shell
Implementation Method 3
using a method involving electroplating or anodic oxidation to form the porous shell
Data Source
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AI summary
Disclosed is an anode for a lithium secondary battery. The anode includes a current collector in the form of a wire and a porous anode active material layer coated to surround the surface of the current collector. The three-dimensional porous structure of the active material layer increases the surface area of the anode. Accordingly, the mobility of lithium ions through the anode is improved, achieving superior battery performance. In addition, the porous structure allows the anode to relieve internal stress and pressure, such as swelling, occurring during charge and discharge of a battery, ensuring high stability of the battery while preventing deformation of the battery. These advantages make the anode suitable for use in a cable-type secondary battery. Further disclosed is a lithium secondary battery including the anode.