Insulated Electrode Sheet Edges for Burr-Induced Short-Circuit Prevention

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Solution Overview

Problem

Existing electrode sheet designs in battery cells face issues with reliability due to burrs and exposed end surfaces causing short circuits and overlapping with electrodes of opposite polarity during the cutting process, which are not adequately addressed by current ceramic coatings.

Innovation Solution

An electrode sheet design featuring a current collector with a first insulating layer of 200 nm to 2000 nm thickness on the end surface and a second insulating layer made of thermoplastic polymer on the transition area, which covers burrs and exposed surfaces, reducing the risk of short circuits and overlapping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ceramic coating is applied to the current collector end surface, then the insulating effect is improved, but the coating cannot adequately cover burrs and exposed surfaces generated during cutting, leading to short circuits

Engineering Contradiction:

Improveinsulating effectVSAvoidcoverage of burrs and exposed surfaces

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the material parameter from ceramic coating to thermoplastic polymer coating. The thermoplastic polymer undergoes phase change during cutting (melting and solidifying), which enables it to dynamically adapt and cover irregular surfaces and burrs that ceramic coatings cannot adequately protect against

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The thermoplastic polymer coating utilizes phase transition (solid-liquid-solid) during the cutting process. When heated by the cutting tool, the coating melts and flows to cover burrs and exposed surfaces, then solidifies upon cooling to provide continuous insulating protection, directly addressing the coverage deficiency of ceramic coatings

Inventive Principle:

Principle #36Phase transitions

2Ease of manufacture

If the current collector end surface is left exposed, then the manufacturing process is simpler, but the exposed surface and burrs overlap with electrodes of opposite polarity causing short circuits

Engineering Contradiction:

Improvesimplicity of manufacturing processVSAvoidrisk of short circuits

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The thermoplastic polymer coating is applied to the current collector end surface before the cutting process. This preliminary coating ensures that when cutting occurs, the burrs and exposed surfaces are already covered with an insulating material, preventing short circuits without adding complex post-processing steps

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The cutting process that generates harmful burrs and exposed surfaces is converted into a beneficial process by using the heat from the cutting tool to melt the thermoplastic polymer coating, which then flows to cover these very burrs and surfaces, turning the harmful effect of cutting into a protective mechanism

Inventive Principle:

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

3Reliability

If a thick insulating layer is applied to cover burrs and exposed surfaces, then the reliability is improved, but the thickness increases the overall size and reduces energy density

Engineering Contradiction:

Improveprotection against short circuitsVSAvoidthickness of insulating layer

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The thermoplastic polymer coating's phase transition capability allows it to provide adequate coverage of burrs and exposed surfaces during cutting, then solidify into a thin, uniform protective layer. This eliminates the need for thick insulating layers, maintaining both reliability and compact dimensions for high energy density

Inventive Principle:

Principle #36Phase transitions

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 design enhances the reliability of battery cells by effectively covering burrs and exposed surfaces, thereby minimizing the risk of short circuits and improving the overall performance and energy density.

Implementation Method 1

When heated to a certain condition, the thermoplastic polymer changes from a solid state to a flowing state. In this way, the thermoplastic polymer in the flowing state may flow to the burrs and the exposed end surface during the process of cutting the current collector provided with the second insulating layer. After the temperature is lowered, the thermoplastic polymer in the flowing state solidifies at the burrs and the exposed end surface to cover the burrs and the exposed end surface

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentUS20250329750A1Electrode sheet and manufacturing method therefor, battery cell, battery, and electric device

Publication Date: 2025.10.23 CONTEMPORARY AMPEREX TECHNOLOGY CO LTD

AI summary

An electrode sheet, a manufacturing method therefor, a battery cell, a battery, and an electric device are provided. The electrode sheet includes a current collector, an active material layer, and a first insulating layer. The current collector comprises a main body and a tab extending from a first end of the main body in a first direction. The main body includes a coating region and a transition region positioned between the coating region and the tab. The active material layer is disposed on the surface of the coating region. The first insulating layer is disposed on the end surface of the main body at the first end and has a thickness of 200 nm to 2000 nm. This configuration improves the reliability of the battery cell.