Cracked Positive Electrode Sheet for Li-Ion Cycle Life
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing secondary batteries, particularly lithium-ion batteries, face challenges in achieving a balance between high energy density and long cycle life, with pre-lithiation technologies increasing production costs and posing safety risks, and conventional methods failing to optimize the cycle performance and capacity retention.
Innovation Solution
A positive electrode sheet with a controlled cracked structure in the positive active material layer, where 5≤a≤20% of the area has a cracked structure, combined with specific particle size distributions and doping elements, to enhance lithium ion replenishment and inhibit particle breakage, thereby improving cycle performance and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-lithiation technology is used to improve cycle performance, then capacity retention is improved, but production cost increases and safety risks arise
Solution Approach 1:
The positive electrode material performs self-lithiation during the first charge cycle, automatically replenishing lithium ions without external intervention. The cracked structure enables internal lithium storage and gradual release, making the system self-sufficient for cycle performance improvement without additional pre-lithiation steps
Solution Approach 2:
The patent changes the structural parameter of the positive electrode material by introducing cracks with controlled width (10-200 nm) and depth (10-5000 nm), creating internal lithium storage spaces that enable self-lithiation behavior, thereby improving cycle performance through structural modification rather than chemical composition changes
2Reliability
If pre-lithiation technology is used to improve cycle performance, then capacity retention is improved, but safety risks increase
Solution Approach 1:
The system uses self-lithiation through the cracked structure instead of external pre-lithiation agents, eliminating safety risks associated with additional lithium sources while maintaining cycle performance improvement
Solution Approach 2:
The patent converts the typically harmful effect of particle cracking (which causes capacity fade) into a beneficial feature by controlling crack dimensions to create internal lithium storage spaces, transforming structural degradation into a self-replenishment mechanism
3Ease of manufacture
If conventional methods are used, then production cost is controlled, but cycle performance and capacity retention are insufficient
Solution Approach 1:
The patent modifies physical parameters (crack width 10-200 nm, depth 10-5000 nm) of existing positive electrode materials to enable self-lithiation, achieving cycle performance improvement through structural parameter optimization rather than material substitution, thus maintaining cost-effectiveness
Solution Approach 2:
The cracks are introduced locally within the positive electrode particles, creating specific regions for lithium storage while maintaining the overall material structure and composition, allowing conventional materials to gain enhanced performance through localized structural modification
Data Source
AI summary
A positive electrode sheet, a secondary battery, a battery pack and an electricity-consumption equipment are provided. The positive electrode sheet includes a positive current collector. At least one surface of the positive current collector is provided with a positive active material layer. In any 25 μm×25 μm region of a cross section of the positive active material layer, a percentage of an area of a first positive active material with a cracked structure to a total area of the region is a %, 5≤a≤20.