Wound Electrode Assembly Bonding Layer for Short-Circuit Heat Control

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Solution Overview

Problem

Existing electrochemical devices have a low pass rate in safety tests such as nailing and heavy object impact, leading to potential short circuits and risks of fire or explosion due to the lack of effective mechanisms to divert short-circuit currents and prevent high-temperature melting at the short-circuit points.

Innovation Solution

An electrochemical device with a winding structure featuring a bonding member composed of a conductive bonding layer and metal layer, strategically positioned on uncoated foil zones of the electrode plates, which enables rapid short-circuiting and enhances mechanical strength, thereby reducing the risk of high-temperature melting and improving safety and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elongated positive uncoated foil zone and negative uncoated foil zone are provided at the ends of the electrode plates to form a vest structure, then the electrochemical device can rapidly short circuit when pierced by an external sharp conductor, but the pass rate of safety tests remains relatively low due to high-temperature melting at the short-circuit point

Engineering Contradiction:

Improvesafety test pass rateVSAvoidtemperature at short-circuit point

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The bonding member acts as an intermediary component between the positive and negative uncoated foil zones. It provides a controlled short-circuit path that diverts current away from the foil zones, preventing high-temperature melting while maintaining the rapid short-circuit function. The bonding member includes a bonding layer and metal layer that facilitate this intermediary function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the harmful effect of high-temperature melting at the short-circuit point into a beneficial outcome by using the bonding member to deliberately create a controlled short-circuit path. The short-circuiting function, which initially causes overheating, is transformed into a safety mechanism that protects the electrode plates while the bonding member dissipates the heat through its specific material properties and structure.

Inventive Principle:

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

2Reliability

If a bonding member is added to improve mechanical strength and enable continuous short-circuiting, then safety and reliability are improved, but the energy density of the electrochemical device is reduced

Engineering Contradiction:

Improvesafety and reliabilityVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The bonding member is strategically positioned only at specific locations where short-circuiting is needed (at the ends of the electrode plates in the uncoated foil zones). This localized placement provides the necessary safety function only where required, rather than throughout the entire device, thereby minimizing the impact on energy density while maintaining improved safety and reliability at critical points.

Inventive Principle:

Principle #3Local quality

3Strength

If the bonding member is disposed on both the first region and the second region, then the mechanical strength is improved and continuous short-circuiting is enhanced, but the impact on energy density increases

Engineering Contradiction:

Improvemechanical strength of uncoated foil zonesVSAvoidenergy density

Core Design Contradiction:

StrengthVSUse of energy by moving object

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

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 bonding member effectively diverts short-circuit currents, ensuring continuous short-circuiting and reducing the risk of fire or explosion, while maintaining energy density by minimizing the impact on the device's thickness and mechanical strength, thus enhancing the safety and reliability of the electrochemical device during mechanical abuse.

Implementation Method 1

the bonding layer includes a conductive material... the first region and the second region may come into contact and conduct through the bonding member, resulting in a short circuit, which diverts a short circuit current within the electrode assembly

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS20250105453A1Electrochemical device and electronic device

Publication Date: 2025.03.27 NINGDE AMPEREX TECHNOLOGY LTD

AI summary

An electrochemical device, including an electrode assembly. The electrode assembly is of a winding structure, including a first electrode plate, a second electrode plate, and a separator disposed between the first electrode plate and the second electrode plate. The first electrode plate includes a first current collector and a first active material layer, the first current collector includes a first uncoated foil zone. The second electrode plate includes a second current collector and a second active material layer, the second current collector includes a second uncoated foil zone. The electrochemical device further includes a bonding member, the bonding member includes a bonding layer and a metal layer stacked together, the bonding layer includes a conductive material, and the bonding member is bonded to at least one of the first uncoated foil zone or the second uncoated foil zone through the bonding layer.