Pouch Cell Elastic Foam Layer for Uniform Pressure Stability

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Solution Overview

Problem

Lithium secondary batteries experience reduced lifespan due to contraction and expansion during charging and discharging, leading to lithium ion precipitation and non-uniform surface pressure, which existing solutions fail to adequately address.

Innovation Solution

Incorporating an elastic foam layer, made from materials like polyurethane, polystyrene, or polyolefin, on the outer surface of pouch cells to provide uniform surface pressure and stabilize the battery during expansion and contraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If pouch cells are stacked without additional stabilization structures, then device complexity is reduced, but the battery experiences contraction and expansion during charging and discharging leading to reduced lifespan

Engineering Contradiction:

Improvebattery lifespanVSAvoidstructure complexity

Core Design Contradiction:

Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

An elastic foam layer is introduced between pouch cells in the stack structure. This foam layer acts as a flexible buffer that accommodates the contraction and expansion of pouch cells during charging and discharging cycles, preventing deformation and extending battery lifespan without requiring complex rigid stabilization structures

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The elastic foam layer utilizes a porous structure that allows it to compress and expand elastically in response to volume changes in the pouch cells. This porous material absorbs mechanical stress from electrode expansion/contraction, preventing lithium ion precipitation and maintaining cell integrity over time

Inventive Principle:

Principle #31Porous materials

2Object-affected harmful factors

If existing flame retardant film solutions are used, then flame retardancy is improved, but lithium ion precipitation occurs and battery lifespan is decreased

Engineering Contradiction:

Improveflame retardancyVSAvoidbattery lifespan

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The elastic foam layer is constructed as a composite material system combining flame retardant properties with elastic mechanical properties. This composite structure provides both fire safety and mechanical buffering capabilities, preventing the lithium ion precipitation issue that occurs with conventional flame retardant films while maintaining flame resistance

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 elastic foam layer enhances the stability and lifespan of lithium secondary batteries by uniformly distributing pressure, preventing deformation and lithium ion precipitation, thereby improving charge/discharge properties.

Implementation Method 1

an elastic foam layer formed on an outer surface of at least one of the plurality of pouch cells

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS12431569B2Lithium secondary battery and method of fabricating the same

Publication Date: 2025.09.30 SK ON CO LTD

AI summary

A lithium secondary battery according to an embodiment of the present invention includes a stack structure including a plurality of pouch cells and an elastic foam layer formed on an outer surface of at least one of the plurality of pouch cells. A uniform pressure may be provided by the elastic foam layer to prevent deformation of the battery due to contraction and expansion of the electrode.