Porous Composite Negative Electrode for Battery Swelling Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing negative electrodes in secondary batteries swell during cycling, leading to insufficient electrolyte infiltration, rapid capacity fade, and reduced cycle life, while attempts to improve this through increased electrolyte content or active material packing density either compromise energy density or safety.
Innovation Solution
A negative electrode with a composite layer structure featuring oval-like active material particles with through holes and blind holes, where the first active material layer has a larger average pore size and porosity than the second active material layer, enhancing liquid absorption, storage capacity, and electronic conductivity, thereby maintaining high energy density and extending cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the packing compactness of active material particles is reduced to increase liquid absorption capability, then cycle life is improved, but negative electrode thickness increases which reduces energy density
Solution Approach 1:
The patent employs porous active material particles with controlled pore structures (through-holes and blind holes) that provide internal liquid storage capacity. This allows the electrode to maintain higher liquid absorption capability with reduced particle packing compactness, thereby improving cycle life while controlling electrode thickness through optimized pore architecture rather than simply increasing overall electrode volume.
Solution Approach 2:
The patent implements a composite layer structure where particles with different pore characteristics are nested in specific sequences - a first layer with particles having larger average pore sizes for primary liquid absorption, and a second layer with particles having smaller average pore sizes for supplemental liquid storage. This nested arrangement optimizes liquid absorption capability across the electrode thickness, improving cycle life while maintaining compact overall structure and energy density.
2Reliability
If more electrolyte is added to maintain sufficient electrolyte content during cycle, then cycle life is prolonged, but internal pressure increases causing cycle expansion and safety problems
Solution Approach 1:
The porous active material particles with controlled pore sizes and distributions provide internal reservoirs that absorb and retain electrolyte within the electrode structure. This internal electrolyte storage mechanism ensures sufficient electrolyte content during cycling without requiring excessive external electrolyte addition, thereby extending cycle life while preventing dangerous increases in internal battery pressure and associated safety issues.
3Quantity of substance
If the negative electrode film uses a composite layer structure with oval-like particles and through holes, then liquid absorption and storage capacity are increased, but device complexity increases
Solution Approach 1:
The patent utilizes porous active material particles with through-holes and blind holes that can be manufactured using established ceramic or polymer processing techniques. These porous structures significantly enhance liquid absorption and storage capacity while maintaining compatibility with conventional electrode fabrication methods, thereby increasing functional capacity without proportionally increasing device complexity.
Solution Approach 2:
The patent employs a composite layer structure combining particles with different pore characteristics in a systematic arrangement. This composite approach optimizes liquid absorption and storage capacity by leveraging the complementary properties of different particle types, achieving enhanced performance while using standard composite material fabrication techniques that do not substantially increase manufacturing complexity.
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 composite layer structure improves active material accumulation, electrolyte infiltration, and ion transport, significantly prolonging the cycle life of secondary batteries while maintaining high energy density and dynamic performance.
Implementation Method 1
the first active material in the first active material layer and the second active material in the second active material layer are oval-like particles with through holes and/or blind holes
Implementation Method 2
secondary batteries complete the charging and discharging process by means of reciprocating intercalation and deintercalation of active ions between positive and negative active materials
Data Source
Figure 1~3
Figure 4~6
Figure 7
AI summary
The present application discloses a negative electrode, a secondary battery (5) and a device comprising the same. The negative electrode includes: a current collector (521); a first active material layer (522) close to the current collector (521), the first active material layer (522) including a first active material; and a second active material layer (523) disposed on a surface of the first active material layer (522) away from the current collector (521), the second active material layer (523) including a second active material; wherein the first active material and the second active material are independently oval-like particles with through holes and/or blind holes, and the first active material has an average pore size greater than that of the second active material.