Lithium Battery Positive Electrode Pore Volume for Crack-Free Rolling
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Solution Overview
Problem
Lithium secondary batteries face challenges in achieving high energy density due to excessive rolling, which leads to particle breakage and internal cracks in the positive electrode active material, resulting in accelerated degradation and reduced battery life.
Innovation Solution
A positive electrode for lithium secondary batteries is developed, featuring a positive electrode active material layer with a specific pore volume of 7.0×10−3·cm3/g to 8.0×10−3·cm3/g, which is achieved through a method involving coating a positive electrode slurry on a collector and rolling it to maintain optimal particle structure and contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If excessive rolling is performed to increase energy density, then energy density is improved, but particle breakage and internal cracks occur
Solution Approach 1:
The invention optimizes the pore volume parameter of the positive electrode active material layer to a specific range (7.0×10−3·cm3/g to 8.0×10−3·cm3/g). By controlling this physical parameter, the electrode structure maintains appropriate porosity that prevents excessive particle breakage and internal crack formation during rolling, while still achieving high energy density. This parameter optimization resolves the contradiction by finding the optimal balance point between compression density and particle integrity.
2Quantity of substance
If rolling is performed to increase energy density, then energy density is improved, but particle breakage occurs leading to increased gas generation
Solution Approach 1:
By precisely controlling the pore volume of the positive electrode active material layer within the range of 7.0×10−3·cm3/g to 8.0×10−3·cm3/g, the invention reduces particle breakage and internal crack formation during rolling. This parameter control minimizes the exposure of fresh particle surfaces to the electrolyte solution, thereby significantly reducing gas generation from side reactions while maintaining high energy density.
3Quantity of substance
If rolling is performed to increase energy density, then energy density is improved, but particle breakage accelerates degradation
Solution Approach 1:
The invention optimizes the pore volume parameter to 7.0×10−3·cm3/g to 8.0×10−3·cm3/g, which maintains particle integrity during rolling and reduces the occurrence of particle breakage and internal cracks. This parameter control prevents accelerated degradation from side reactions with the electrolyte solution, thereby extending battery life while achieving high energy density.
Data Source
AI summary
disclosure A positive electrode for a lithium secondary battery includes a positive electrode collector; and a positive electrode active material layer which is formed on at least one surface of the positive electrode collector and includes a positive electrode active material, wherein the positive electrode active material layer has a pore volume of 7.0×10−3·cm3/g to 8.0×10−3·cm3/g. A method for preparing the positive electrode is also provided.