Porous Support Layers for Flexible Electrodes Under Bending Stress

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing flexible secondary batteries suffer from detachment of the electrode active material layer due to external forces and rapid volume swelling, leading to decreased capacity and degraded cycle life characteristics, and increasing binder content exacerbates electrode resistance.

Innovation Solution

A flexible electrode design featuring conductive coating layer-containing porous polymer substrates as support layers on either side of the electrode, with a porous structure to buffer external forces and maintain electrical conductivity, using a conductive material and dispersing agent to minimize resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If binder content in the electrode layer is increased to improve flexibility against bending or distortion, then flexibility is improved, but electrode resistance increases resulting in degradation of battery performance

Engineering Contradiction:

ImproveflexibilityVSAvoidbattery performance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent employs a flexible polymer substrate (such as polyimide or polyester) as the electrode base instead of traditional rigid metal foils. This flexible substrate inherently provides bending and distortion resistance without requiring excessive binder content, thus maintaining low electrode resistance while achieving the desired flexibility for wearable and deformable battery applications.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent uses composite electrode structures combining active material particles with conductive additives and minimal binder content on a flexible substrate. This composite approach optimizes the balance between mechanical flexibility and electrical conductivity, allowing the electrode to bend without cracking while maintaining low resistance for good battery performance.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If severe external force is applied to achieve compact folding of the electrode, then portability is improved, but the composite type electrode shows limitation in flexibility causing detachment of the electrode

Engineering Contradiction:

Improvefolding capabilityVSAvoidelectrode integrity

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The flexible polymer substrate acts as a robust yet compliant base that can withstand severe folding and external forces. Unlike rigid metal foils, the flexible substrate maintains its structural integrity during compact folding, preventing electrode detachment while enabling the battery to achieve space-saving folded configurations for portable applications.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent incorporates buffer layers or cushioning structures between the electrode and external environment to absorb and distribute mechanical stress during folding. This pre-cushioning approach protects the electrode from concentration stresses that would otherwise cause detachment, enabling reliable folding without compromising electrode integrity.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If the electrode layer has high adhesion to the current collector, then electrode stability is improved, but cracking is generated in the electrode layer in the vertical direction of the current collector causing short-circuit

Engineering Contradiction:

Improveelectrode adhesionVSAvoidcracking and short-circuit

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The flexible polymer substrate replaces traditional rigid current collectors, providing high adhesion to the electrode layer while accommodating volume changes and mechanical deformation. This flexibility prevents the generation of vertical cracks that would occur with rigid substrates, thereby eliminating the short-circuit risk while maintaining stable electrode adhesion throughout charge-discharge cycles.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent modifies the mechanical properties of the substrate from rigid to flexible, changing its ability to accommodate electrode expansion and contraction. This parameter change allows the substrate to maintain strong adhesion while flexing with the electrode, preventing crack formation and avoiding short-circuits during battery operation.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12407000B2Flexible electrode, secondary battery including the same, and flexible secondary battery

Publication Date: 2025.09.02 LG ENERGY SOLUTION LTD

AI summary

A flexible electrode includes: a current collector; an electrode layer positioned at a top of the current collector; a first support layer positioned at a top of the electrode layer; and a second support layer positioned at a bottom of the current collector, wherein each of the first support layer and the second support layer is a conductive coating layer-containing porous polymer substrate including a porous polymer substrate, and a conductive coating layer positioned on a surface of the porous polymer substrate and including a conductive material and a dispersing agent, and the porous polymer substrate is a non-woven web provided with a plurality of polymer fibers and a pore structure interconnected by the plurality of polymer fibers.