Positive Electrode Layer Structure for Balanced Battery Conductivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lithium batteries face challenges in achieving balanced conductivity across different regions of the positive electrode plate, leading to lithium ion deintercalation imbalance and affecting cycling and rate performance.
Innovation Solution
A positive electrode plate design with a first film layer containing lithium transition metal phosphate and carbon coating, and a second film layer containing lithium transition metal oxide and a conductive agent, with a controlled resistivity difference of 10-200 Ω·cm, to improve conductivity and reduce lithium ion deintercalation imbalance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single film layer is used in the positive electrode plate, then the structure is simple, but the conductivity is uneven across different regions leading to lithium ion deintercalation imbalance
Solution Approach 1:
The positive electrode plate is divided into a first film layer containing lithium transition metal phosphate and a second film layer containing lithium transition metal oxide, with each layer having different resistivity characteristics. This segmentation allows different regions of the electrode to have optimized conductivity properties, preventing lithium ion deintercalation imbalance while maintaining manageable structural complexity through systematic layering.
Solution Approach 2:
The first film layer and second film layer are designed with different resistivity values (10-200 Ω·cm difference) to create local conductivity variations matched to the specific electrochemical properties of each material system. This local quality optimization ensures that each film layer's conductivity characteristics are tailored to its active material, preventing overall conductivity imbalance without requiring complex heterogeneous structures throughout the entire electrode.
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 design enhances the cycling and rate performance of lithium batteries by balancing conductivity and reducing internal resistance, while maintaining energy density and specific capacity.
Implementation Method 1
The conductive agent added to the second film layer with a large resistivity value may reduce the overall resistivity of the second film layer and improve conductivity of the second film layer
Implementation Method 2
the first film layer includes a lithium transition metal phosphate and a carbon coating applied on at least part of the surface of the lithium transition metal phosphate
Data Source
AI summary
Embodiments of the present application provide a positive electrode plate, a secondary battery and an electrical apparatus. The positive electrode plate includes a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, where the positive electrode film layer includes a first film layer and a second film layer in a thickness direction of the positive electrode plate; the first film layer includes a lithium transition metal phosphate and a carbon coating applied on at least part of the surface of the lithium transition metal phosphate, and the second film layer includes a lithium transition metal oxide and a conductive agent; and a resistivity difference between the second film layer and the first film layer is 10-200 Ω·cm.