Flexible Battery Electrode Stress Buffering

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Solution Overview

Problem

Conventional rechargeable batteries with flexible characteristics face durability issues due to repeated bending, as uncoated regions are prone to damage from compressive and tensile stresses, leading to potential internal short circuits.

Innovation Solution

Incorporating stress buffering parts made of ethylene propylene copolymer, hydrogenated hydrocarbon polymer, and polyethylene films on uncoated regions of the electrodes, which are applied to partial areas of the electrode assembly to absorb stress and prevent damage during bending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If flexible rechargeable batteries are designed to be bendable, then flexibility is improved, but durability deteriorates due to stress damage to uncoated regions

Engineering Contradiction:

ImproveflexibilityVSAvoiddurability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

A stress buffering part made of flexible material (ethylene propylene copolymer, hydrogenated hydrocarbon polymer, or polyethylene) is attached to the uncoated region of the electrode before bending occurs. This cushioning layer absorbs compressive and tensile stresses during bending, preventing damage to the electrode tab and maintaining electrical connectivity, thus resolving the contradiction between flexibility and durability

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The stress buffering part is constructed from composite flexible materials including ethylene propylene copolymer, hydrogenated hydrocarbon polymer, and/or polyethylene. These composite materials provide both the flexibility needed for bending and the mechanical strength to buffer stresses, simultaneously achieving adaptability and reliability

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If uncoated regions are left exposed on electrodes, then manufacturing simplicity is maintained, but reliability deteriorates due to susceptibility to stress damage

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoiddurability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The electrode structure is segmented into coated regions (active material) and uncoated regions (electrode tab), with the stress buffering part selectively attached only to the uncoated region. This segmentation protects the vulnerable electrode tab area while maintaining the functional coated regions, improving reliability without complicating the overall manufacturing process

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stress buffering part is attached only to the uncoated region where it is most needed for stress protection, rather than covering the entire electrode. This localized approach maintains manufacturing simplicity while providing targeted protection to the vulnerable electrode tab area, resolving the contradiction between ease of manufacture and reliability

Inventive Principle:

Principle #3Local quality

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 solution significantly enhances the durability and flexibility of rechargeable batteries by preventing damage to electrode tabs and maintaining electrical connectivity, even with repeated bending, thus improving the battery's overall performance.

Implementation Method 1

at least one of a first stress buffering part on at least a partial region of the first uncoated region and a second stress buffering part on at least a partial region of the second uncoated region

Methodology Applied

Scientific EffectStress buffering: Elasticity

Implementation Method 2

configured as a film including an ethylene propylene copolymer, a hydrogenated hydrocarbon polymer, and polyethylene

Methodology Applied

Scientific EffectStress absorption: Damping

Data Source

PatentUS11056710B2Electrode assembly for flexible rechargeable battery and flexible rechargeable battery including the same

Publication Date: 2021.07.06 SAMSUNG SDI CO LTD

AI summary

An electrode assembly and a rechargeable battery including the same are provided. An electrode assembly for a rechargeable battery includes: a first electrode including a first coating part and a first uncoated region at at least one side of the first coating part; a second electrode including a second coating part and a second uncoated region at at least one side of the second coating part; a separator between the first electrode and the second electrode; and at least one of a first stress buffering part on at least a partial region of the first uncoated region and a second stress buffering part on at least a partial region of the second uncoated region, the at least one of the first stress buffering part and the second stress buffering part being configured as a film including an ethylene propylene copolymer, a hydrogenated hydrocarbon polymer, and polyethylene.