Battery Separator Edge Texture for Precise Electrode Stacking

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Solution Overview

Problem

Existing separator technologies face challenges in preventing deviation during transfer and ensuring proper alignment and adhesion between the separator and electrodes in lithium secondary battery assembly, leading to potential misalignment and short circuits.

Innovation Solution

A polyolefin-based separator with an uneven portion formed along its outer periphery to prevent slip and deviation, featuring a non-coating portion with a coating portion on the remaining part, allowing for stable fixation and thermal fusion during electrode assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a separator is transferred in a roll-to-roll manner during manufacturing, then productivity is improved, but the separator may slip from the transfer roll and deviate from the movement direction

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidseparator alignment

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The uneven portions are formed on the separator surface before the coating process, creating friction-enhanced regions that prevent slip during subsequent transfer operations. This preliminary structural modification ensures the separator maintains its position during high-speed roll-to-roll manufacturing without compromising alignment precision

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The coating layer is selectively applied to specific regions of the separator, with uneven portions created in non-coating regions. This local differentiation allows the separator to have both smooth coated areas for ion conduction and textured non-coated areas for enhanced friction and slip prevention during transfer

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If the separator deviates from the movement direction during transfer, then manufacturing is simplified, but the electrode position changes and electrodes may not be aligned

Engineering Contradiction:

Improvetransfer process simplicityVSAvoidelectrode alignment

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The uneven portions are pre-formed on the separator to create friction-enhanced regions that maintain separator position during transfer. This preliminary structural feature ensures that even during simplified transfer operations, the separator remains aligned with the electrodes, preventing position deviations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The uneven portions create asymmetric surface characteristics on the separator, with increased friction in specific regions. This asymmetry provides directional stability during transfer, ensuring the separator maintains its intended orientation and alignment with electrodes throughout the manufacturing process

Inventive Principle:

Principle #4Asymmetry

3Device complexity

If only lamination process is used to join separator and electrode, then device complexity is reduced, but adhesive force is insufficient and separator may fold causing short circuit

Engineering Contradiction:

Improvejoining process complexityVSAvoidadhesive strength

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The uneven portions are strategically positioned in non-coating regions where they provide enhanced mechanical interlocking. This local structural modification creates high-friction zones that significantly improve adhesive force between separator and electrode, preventing folding and short circuits while maintaining a relatively simple lamination process

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The separator structure combines smooth coated regions for ionic conduction with textured non-coated regions for enhanced mechanical bonding. This composite structure provides both the necessary electrical functionality and improved adhesion through the uneven portions, achieving reliable joining with reduced process complexity

Inventive Principle:

Principle #40Composite materials

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 uneven portion enhances friction and adhesion, preventing separator deviation and misalignment, ensuring stable electrode positioning and preventing short circuits by improving the adhesive force through thermal fusion.

Implementation Method 1

The uneven portion enhances friction and adhesion, preventing separator deviation and misalignment

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

a coating layer including an inorganic material and a binder is formed on a polyolefin-based separator substrate

Methodology Applied

Scientific EffectComposite materials: Composite Materials

Implementation Method 3

a thermally fused section is formed in a non-coating region in which the coating layer is not formed

Methodology Applied

Scientific EffectThermal fusion: Welding

Data Source

PatentUS20230378611A1Separator including uneven portion, electrode assembly including the same, and method of manufacturing electrode assembly

Publication Date: 2023.11.23 LG ENERGY SOLUTION LTD

AI summary

A separator includes a polyolefin-based separator substrate and a coating portion formed on at least a part of an outer surface of the separator substrate. An uneven portion is formed along an outer periphery of at least one side of the separator, whereby it is possible to prevent deviation of a separator sheet from a movement direction during transfer of the separator sheet and stacking of an electrode assembly.