Positive Electrode Sheet With Cracked Active Material for Cycle Retention
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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 percentage of cracked structure in the positive active material layer, combined with specific particle size distributions and doping elements, to regulate the extraction and retention of lithium ions, enhancing the cycle performance and capacity of lithium-ion batteries.
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 active material itself provides lithium ions through its cracked structure to replenish the SEI membrane, eliminating the need for external pre-lithiation processes. The material serves its own function of maintaining lithium ion balance without requiring additional manufacturing steps or materials.
Solution Approach 2:
The patent changes the physical structure parameter of the positive active material by creating a controlled cracked structure. This structural modification enables the material to release lithium ions on demand, fundamentally altering how the material contributes to cycle performance without changing the manufacturing process complexity.
2Reliability
If pre-lithiation technology is used to improve cycle performance, then capacity retention is improved, but safety risks increase
Solution Approach 1:
The positive active material autonomously provides lithium ions through its cracked structure to maintain the SEI membrane integrity. This self-service mechanism eliminates the need for external pre-lithiation agents that could pose safety risks, as the lithium ions are released in a controlled manner from within the material structure itself.
Solution Approach 2:
The patent converts the typically harmful effect of SEI membrane lithium ion consumption (which degrades cycle performance) into a beneficial self-regulating system. The cracked structure allows controlled lithium ion release that正好 compensates for SEI formation, turning a degradation mechanism into a self-healing feature.
3Ease of manufacture
If conventional methods are used to optimize cycle performance, then manufacturing simplicity is maintained, but capacity retention deteriorates
Solution Approach 1:
The patent modifies the physical structure parameter of the positive active material by creating a controlled cracked structure with specific morphology. This structural change enables the material to release lithium ions, fundamentally improving capacity retention while maintaining compatibility with conventional manufacturing processes.
Solution Approach 2:
The positive electrode comprises a composite structure where the cracked positive active material works synergistically with the binder and conductive agents. This composite approach allows the cracked structure to provide lithium ions while the other components maintain structural integrity and electrical conductivity, achieving improved performance without complicating manufacturing.
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 proposed solution improves the cycle performance and capacity retention of lithium-ion batteries by balancing initial efficiency with long-term durability, reducing operating costs and enhancing energy storage device service life.
Implementation Method 1
a first positive active material with a cracked structure... capable of extracting lithium ions to replenish a solid electrolyte interphase membrane
Data Source
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Figure 3~4
AI summary
The present application provides a positive electrode sheet, a secondary battery, a battery pack and an electricity-consumption equipment. 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 25µm×25µm 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.