Layered Positive Electrode Plate for Shrinkage-Matched Cathodes

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The dynamic performance of lithium-ion secondary batteries is compromised due to asynchronous shrinkage and expansion of active materials with different shrinkage rates when mixed in a single layer, leading to poor conductive network contact and increased impedance.

Innovation Solution

A positive electrode plate is designed with at least two active material layers, where the maximum shrinkage rates of adjacent layers differ by ≥0.3%, with specific particle size distributions and layering configurations to synchronize material expansion and contraction, enhancing conductive network stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If different active materials with greatly different shrinkage rates are mixed into a single slurry layer, then the manufacturing process is simple, but the conductive network deteriorates due to asynchronous shrinkage and expansion, reducing dynamic performance

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidconductive network stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The positive electrode active material layer is segmented into multiple sub-layers, each containing active materials with similar shrinkage rates. This segmentation prevents asynchronous shrinkage and expansion that would occur in a mixed single layer, thereby maintaining conductive network stability while still allowing for simplified manufacturing of each individual sub-layer

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the positive electrode active material layer are designed with different compositions - each sub-layer has a specific combination of active materials tailored to have matched shrinkage characteristics. This local quality control ensures that each region shrinks and expands synchronously, preserving the conductive network in its respective zone

Inventive Principle:

Principle #3Local quality

2Reliability

If different active materials are arranged in separate layers with different shrinkage rates, then the conductive network stability is improved, but the device structure becomes more complex

Engineering Contradiction:

Improveconductive network stabilityVSAvoidlayered structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The positive electrode active material layer is divided into multiple sub-layers, each containing active materials with similar shrinkage rates. This segmentation prevents asynchronous shrinkage and expansion that would occur in a mixed single layer, thereby maintaining conductive network stability while still allowing for simplified manufacturing of each individual sub-layer

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shrinkage rate parameter is controlled and matched within each sub-layer by selecting specific combinations of active materials. By ensuring that active materials within the same sub-layer have similar shrinkage characteristics, the patent maintains conductive network stability without requiring overly complex multi-layer structures

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If active materials with different shrinkage rates are physically mixed, then the energy density is improved through material diversity, but the impedance increases due to poor conductive network contact

Engineering Contradiction:

Improveenergy densityVSAvoidimpedance

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each sub-layer is designed as a composite material system containing multiple active materials with matched shrinkage rates. This composite approach allows the patent to benefit from the diverse electrochemical properties of different materials while avoiding the harmful effects of asynchronous shrinkage, thus maintaining low impedance through stable conductive network contact

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS20250329721A1Positive electrode plate, electrode assembly, battery cell, battery, and electrical device

Publication Date: 2025.10.23 CONTEMPORARY AMPEREX TECHNOLOGY CO LTD

AI summary

A positive electrode plate comprises at least two active material layers, wherein two adjacent active material layers respectively comprise a first positive electrode active material and a second positive electrode active material; and under the same test condition, the maximum shrinkage rate of the first positive electrode active material during charging and discharging is T1, the maximum shrinkage rate of the second positive electrode active material during charging and discharging is T2, and T1 and T2 satisfy the following relationship: T1−T2≥0.3%. Compared with a single-layer positive electrode active material layer formed by directly physically mixing the first positive electrode active material and the second positive electrode active material, when T1−T2 of the first positive electrode active material and the second positive electrode active material is ≥0.3%, the positive electrode plate is provided to include at least two positive electrode active material layers.