Layered Silicon-Graphite Anode Binders for Stable Battery Capacity
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Solution Overview
Problem
Lithium secondary batteries face challenges in mechanical stability and lifespan due to mechanical deformation caused by changes in anode binders, which affect the battery's capacity and output.
Innovation Solution
A lithium secondary battery design featuring a multi-layered anode active material structure with a first layer using a styrene-butadiene rubber (SBR) binder and a second layer using an acryl-based binder, along with a mixture of silicon and graphite-based active materials, to enhance adhesion and prevent electrode expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If anode binder is changed to accommodate new anode materials, then battery capacity and output can be improved, but mechanical deformation of the anode occurs and stability deteriorates
Solution Approach 1:
The anode active material layer is divided into multiple layers, each containing different anode active materials and binders. This segmentation allows each layer to be optimized for specific functions while working together to improve overall battery performance and stability.
Solution Approach 2:
The invention uses composite binder systems where different binders are combined in multiple layers. Each layer contains a specific binder composition that complements the anode active materials in that layer, creating a composite structure that provides both high capacity and mechanical stability.
2Productivity
If silicon-based active material is used to increase capacity, then battery output is improved, but electrode expansion and mechanical deformation occur
Solution Approach 1:
Silicon-based active materials are distributed across multiple layers rather than concentrated in a single layer. This segmentation reduces the overall expansion stress on the electrode structure while maintaining high capacity output.
Solution Approach 2:
The invention changes the physical and chemical parameters of the binder system to accommodate silicon-based materials. By adjusting binder composition and layer structure, the system manages the expansion parameters of silicon during charge-discharge cycles.
3Ease of manufacture
If single-layer anode structure is used for simplicity, then manufacturing is easier, but mechanical stability and lifespan are reduced
Solution Approach 1:
The anode is structured as multiple layers that can be applied sequentially in a systematic manufacturing process. While more complex than a single layer, this segmented structure provides better mechanical stability and lifespan through controlled material distribution and binder optimization.
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 improves mechanical and chemical stability, prevents electrode wrinkling, and enhances the battery's capacity and output by effectively managing the expansion of silicon-based active materials.
Implementation Method 1
a first anode binder containing a styrene-butadiene-based rubber (SBR) binder and a second anode binder containing an acryl-based binder
Implementation Method 2
Each of the first anode active material and the second anode active material includes a silicon-based active material and a graphite-based material
Data Source
AI summary
A lithium secondary battery includes a cathode, a separator, and an anode including an anode current collector and an anode active material layer formed on the anode current collector and facing the cathode with the separator interposed therebetween. The anode active material layer includes a first anode active material layer formed on the anode current collector and including a first anode active material and a first anode binder containing a styrene-butadiene-based rubber (SBR) binder and a second anode active material layer formed on the first anode active material layer and including a second anode active material and a second anode binder containing a acryl-based binder. Each of the first anode active material and the second anode active material includes a silicon-based active material and a graphite-based material and contains 2 to 9.5 parts by weight of silicon with respect to the 100 part by weight of the graphite-based active material.