Rounded Jelly-Roll Electrode Assembly for Crack Prevention

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Solution Overview

Problem

Jelly-roll type electrode assemblies in secondary batteries experience cracking and disconnection due to repeated contraction and expansion during charging and discharging, leading to safety issues such as short circuits and potential ignition.

Innovation Solution

The electrode assembly design includes a positive electrode edge portion and a sealing portion with rounded corners, surrounded by a sealing member, to disperse stress and prevent cracking and short circuits during expansion and contraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the positive electrode and negative electrode are wound in a jelly-roll structure, then the manufacturing ease and energy density per weight are improved, but the electrode assembly is subjected to contraction and expansion during charging/discharging cycles, causing bending deformation, cracks, and disconnection at the electrode end portions

Engineering Contradiction:

Improvemanufacturing easeVSAvoidelectrode assembly stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies curvature by rounding the end portions of the positive electrode. Specifically, the end portion of the positive electrode is formed with a rounded shape having a radius of curvature of 0.5 mm to 5 mm, which prevents stress concentration during charging/discharging cycles and avoids cracking and disconnection while maintaining the jelly-roll winding structure

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Duration of action of moving object

If the electrode assembly undergoes repeated charging and discharging cycles, then the battery provides sustained power, but the contraction and expansion cause bending deformation from the end portion of the positive electrode in the center, resulting in cracks and disconnection or short circuit

Engineering Contradiction:

Improvecharging/discharging cyclesVSAvoidcracks and disconnection

Core Design Contradiction:

Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The rounded end portion design with a specific radius of curvature (0.5 mm to 5 mm) eliminates sharp corners that would concentrate stress during expansion and contraction, thereby preventing cracks and disconnection that occur after repeated charging/discharging cycles

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent applies beforehand cushioning by providing a sealing portion that surrounds the rounded end portion of the positive electrode. This sealing portion acts as a protective barrier that cushions against stress concentration and prevents harmful effects before they can occur during charging/discharging cycles

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS20260081205A1Electrode Assembly, Manufacturing Method Therefor, and Secondary Battery, Battery Pack and Transportation Means Including Electrode Assembly

Publication Date: 2026.03.19 LG ENERGY SOLUTION LTD

AI summary

A jelly-roll type electrode assembly in which a positive electrode, a separator, and a negative electrode are wound. The positive electrode includes a positive electrode edge portion adjacent to a winding center portion and a sealing portion surrounding the positive electrode edge portion. The positive electrode edge portion and the sealing portion each have at least a portion rounded. A method for manufacturing the jelly-roll type electrode assembly, and a secondary battery, a battery pack, and a moving means including the jelly-roll type electrode assembly are also disclosed.