Positive Electrode Sheet Composition for Controlled Lithium Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Secondary batteries, particularly those using lithium-ion technology, suffer from poor charging capacity due to the low gram capacity of commonly used positive electrode materials like lithium iron phosphate, which limits their performance in various electronic devices.
Innovation Solution
Incorporating a lithium supplement additive into the positive electrode sheet, controlled by the relational expression R≤Cmin/(100*m*Q), where R is the mass percentage content, Cmin is the minimum rate value, m is the loading capacity per unit area, and Q is the theoretical gram capacity, allows for slow and continuous lithium supplementation during the cycle process, enhancing charging capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium iron phosphate or other commonly used positive electrode materials are applied to secondary batteries, then the batteries have characteristics of large capacity and long service life, but the charging capacity during use is poor
Solution Approach 1:
The patent changes the chemical composition parameters of the positive electrode by introducing a lithium supplement additive with specific gram capacity. This additive contains lithium-rich compounds that supplement lithium ions during cycling, directly addressing the poor charging capacity issue while maintaining the stable cycle life characteristics of lithium iron phosphate materials.
Solution Approach 2:
The patent creates a composite positive electrode material by combining lithium iron phosphate (or other base materials) with a lithium supplement additive. This composite structure allows the base material to provide stable cycle life while the lithium-rich additive continuously supplements lithium ions, thereby improving charging capacity without sacrificing reliability.
2Quantity of substance
If the mass percentage content of the lithium supplement additive is increased to improve charging capacity, then the gram capacity increases, but the control over slow and continuous lithium supplementation becomes difficult
Solution Approach 1:
The patent establishes a quantitative relationship R≤Cmin/(100*m*Q) that acts as a feedback control mechanism. By calculating the maximum permissible content R based on the minimum rate value Cmin, loading capacity m, and theoretical gram capacity Q, the patent ensures that the lithium supplement additive releases lithium ions at a controlled, slow rate during cycling, preventing excessive or uncontrolled supplementation.
Solution Approach 2:
The patent optimizes the mass percentage content parameter R of the lithium supplement additive within a specific range (0.1%≤R≤20%, preferably 1%≤R≤10%). This parameter optimization ensures sufficient lithium supplementation to improve gram capacity while maintaining the slow and continuous release characteristic controlled by the relational expression, balancing performance improvement with manufacturing control.
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 lithium supplement additive slowly delithiates, releasing capacity continuously, thereby improving the charging capacity and cycle life of the battery cell and secondary battery.
Implementation Method 1
By controlling the mass percentage content of the lithium supplement additive, it is helpful for the lithium supplement additive to slowly de-lithiate during the cycle process, so that its capacity can be slowly and continuously released
Data Source
AI summary
A positive electrode sheet, a battery cell, a secondary battery, and an electric device are provided. The positive electrode sheet includes a positive electrode active material and a lithium supplement additive. The lithium supplement additive satisfies the relationship: R≤Cmin/(100×m×Q), where m is the loading per unit area of the positive electrode sheet (including the total mass of the active material and the lithium supplement additive), Cmin is the minimum rate value applied to the electrode sheet during actual use, is the theoretical specific capacity of the lithium supplement additive, and R is the mass percentage of the lithium supplement additive in the total loading per unit area. This configuration helps ensure lithium balance during battery operation and contributes to performance stability.