Segmented Negative Electrode Plate for Lithium Plating Control

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Solution Overview

Problem

Existing secondary batteries face challenges in achieving good cycling performance and safety performance simultaneously, particularly due to lithium precipitation caused by electrolyte extrusion during expansion and contraction of the negative electrode.

Innovation Solution

A negative electrode plate design with distinct regions, one without solid electrolyte and one with solid electrolyte, strategically positioned to manage electrolyte extrusion, ensuring normal ion de-intercalation and preventing lithium precipitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the negative electrode plate uses a uniform structure without solid electrolyte, then the manufacturing process is simple, but lithium precipitation occurs due to electrolyte extrusion during expansion and contraction

Engineering Contradiction:

Improvecycling performanceVSAvoidelectrode structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The negative electrode plate is divided into multiple regions along the width direction: a first region without solid electrolyte, a second region with solid electrolyte positioned in the middle, and a third region without solid electrolyte. This segmentation allows different parts of the electrode to serve different functions - the middle region with solid electrolyte prevents lithium precipitation during expansion, while the side regions maintain simple structure for easy manufacturing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The solid electrolyte is locally introduced only in the second region (middle portion) of the negative electrode plate where it is most needed to prevent lithium precipitation during expansion. The first and third regions maintain their original structure without solid electrolyte, thus preserving manufacturing simplicity while achieving the desired performance improvement in the critical middle region.

Inventive Principle:

Principle #3Local quality

2Reliability

If the solid electrolyte is added to the entire negative electrode plate, then lithium precipitation is prevented, but the energy density decreases due to excessive solid electrolyte content

Engineering Contradiction:

Improveprevention of lithium precipitationVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The negative electrode plate is segmented into regions with and without solid electrolyte. The solid electrolyte is confined to the second region (middle portion) with width ratio L2/L between 0.1 and 0.5, preventing lithium precipitation only where most needed while preserving energy density in the first and third regions that do not contain solid electrolyte.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of adding solid electrolyte to the entire electrode plate (excessive action), the invention applies solid electrolyte partially only to the middle second region where it is most effective at preventing lithium precipitation during expansion. This partial application achieves the necessary protection while minimizing the amount of solid electrolyte used, thus preserving energy density.

Inventive Principle:

Principle #16Partial or excessive action

3Quantity of substance

If the middle region of the negative electrode plate expands during charging, then more lithium can be stored, but electrolyte is extruded causing lithium precipitation

Engineering Contradiction:

Improvelithium storage capacityVSAvoidelectrolyte extrusion and lithium precipitation

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The solid electrolyte is pre-introduced into the second region (middle portion) of the negative electrode plate before charging occurs. This preliminary anti-action counteracts the harmful effect of electrolyte extrusion that would normally occur during expansion, allowing the middle region to expand and store more lithium without causing lithium precipitation.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The invention converts the harmful electrolyte extrusion effect into a beneficial outcome by introducing solid electrolyte in the middle region. The solid electrolyte acts as a buffer that absorbs the expansion stress, preventing liquid electrolyte from being extruded and causing lithium precipitation, thus allowing greater lithium storage in the expanding middle region.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS12586792B2Negative electrode plate and preparation method therefor, secondary battery, battery module, battery pack and power consuming device

Publication Date: 2026.03.24 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

AI summary

A negative electrode plate may comprise a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector; the negative electrode film layer may comprise a first region and a second region along the width direction, the first region may not comprise a solid electrolyte, while the second region may comprise a solid electrolyte.