Acryl Binder Anode for Lithium Battery Stability
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Solution Overview
Problem
Lithium secondary batteries face challenges in mechanical stability and lifespan due to mechanical deformation caused by conventional binders when using alternative anode active materials, leading to electrode instability and capacity degradation.
Innovation Solution
The use of an acryl-based binder in the anode active material layer, combined with silicon-based anode active materials, and adjusting the binder content and distance between electrode tabs to satisfy a specific ratio, suppresses electrode wrinkles and volume expansion, enhancing mechanical and chemical stability and extending the battery's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional binders are used with alternative anode active materials, then the battery can achieve higher capacity, but mechanical deformation occurs leading to deteriorated stability and lifespan
Solution Approach 1:
The patent changes the chemical composition parameters of the binder from conventional options to a specific copolymer structure containing carboxylic acid groups and hydroxyl groups. This parameter change in binder chemistry enables effective bonding with alternative anode materials while maintaining mechanical stability and preventing deformation during cycling, thus resolving the contradiction between capacity and reliability.
Solution Approach 2:
The patent employs a composite binder system comprising a copolymer of acrylic acid and another monomer, creating a composite material that combines the benefits of high capacity compatibility with mechanical stability. This composite approach allows the binder to simultaneously handle the volumetric expansion of alternative anode materials and maintain structural integrity, resolving the stability-lifespan issue.
2Quantity of substance
If alternative anode active materials are used to increase capacity, then energy density improves, but electrode wrinkles and volume expansion occur
Solution Approach 1:
The patent modifies the binder's chemical structure parameters to include specific functional groups (carboxylic acid and hydroxyl) that can form strong interactions with alternative anode materials. This parameter change enables the binder to accommodate volume expansion and prevent electrode wrinkling, allowing high energy density materials to be used without shape degradation.
3Strength
If binder content is increased to improve mechanical stability, then electrode strength improves, but volume expansion increases
Solution Approach 1:
The patent changes the binder composition parameters to use a copolymer with optimized molecular weight and functional group content. This parameter optimization provides high mechanical strength at lower binder concentrations, preventing both electrode weakness and excessive volume expansion. The specific copolymer structure achieves maximum strength-to-volume ratio.
Data Source
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AI summary
A lithium secondary battery includes an anode including an anode current collector and an anode active material layer formed thereon, the anode active material layer including an acryl-based binder, a cathode facing the anode, an anode tab electrically connected to the anode, and a cathode tab electrically connected to the cathode. A content of the acryl-based binder and a distance between the cathode tab and the anode tab satisfies a predetermined relation to provide the lithium secondary battery having improved mechanical stability and battery performance.