Zigzag Separator Electrode Assembly for Higher Stack Density

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Solution Overview

Problem

The existing electrode assemblies in secondary batteries suffer from reduced energy density due to the formation of spaces between the side portion of the separator and the electrode, resulting from the separator surrounding the outermost portion of the stack, which leads to wrinkles and inefficient use of space.

Innovation Solution

The electrode assembly is designed with a first separator folded in a zigzag configuration, featuring spacer sections and side sections, where the second separator is bonded to the side sections of the first separator, condensing the stack and reducing the space between the outermost separator and the stack.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the separator surrounds the outermost portion of the stack, then the electrode assembly is formed with complete coverage, but spaces and wrinkles are formed between the separator and electrode, reducing energy density

Engineering Contradiction:
Improvecomplete separator coverageVSAvoidenergy density
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The separator is divided into multiple sections: a body portion that contacts the electrode and an outer portion that extends beyond the electrode edges. This segmentation allows the separator to provide complete coverage while preventing space formation between the separator and electrode, thereby maintaining energy density.

Inventive Principle:
Principle #1Segmentation

2Volume of stationary object

If the separator is folded in zigzag configuration, then the stack is condensed and space is reduced, but the structure becomes more complex

Engineering Contradiction:
Improvestack volumeVSAvoidseparator structure
Core Design Contradiction:
Volume of stationary objectVSDevice complexity

Solution Approach 1:

The separator is configured with a curved or zigzag shape where the body portion extends in a direction substantially perpendicular to the electrode surface. This curved configuration allows the separator to condense the stack and reduce space while maintaining structural integrity and simplicity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

This design increases the electrode density and energy density by condensing the space between the outermost separator and the stack, allowing for easier accommodation within battery casings of varying sizes without compromising manufacturing flexibility.

Implementation Method 1

by heating and compressing the side of the stack

Methodology Applied
Scientific EffectHeating and compressing:

Data Source

PatentEP4718554A1Electrode assembly
Publication Date: 2026.04.01 LG ENERGY SOLUTION LTD
  • EP4718554A1 patent drawingFigure 1
  • EP4718554A1 patent drawingFigure 2
  • EP4718554A1 patent drawingFigure 3

AI summary

An electrode assembly includes a stack and a second separator. The stack includes first and second electrodes and a first separator folded in a zigzag configuration and including spacer sections and respective side sections between the spacer sections. The first and the second electrodes are alternately disposed between first separator spacer sections The second separator extends along an upper surface, a lower surface, and at least one pair of opposing side surfaces of the stack. The side sections of the first separator define portions of the side surfaces of the stack on which the first electrode and the second electrode are not disposed. The second separator is bonded to at least one of the side sections.