Flexible Battery Container Corner Folding Mechanism

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Solution Overview

Problem

The existing secondary battery configurations with flexible laminate film containers face issues of mechanical strength weakness, potential damage and deformation of the battery electrode assembly, and difficulty in injecting and holding a sufficient amount of electrolyte due to complex manufacturing steps and reduced electrolyte space.

Innovation Solution

A secondary battery design where the battery electrode assembly has a quadrangular planar shape with four corners folded or inserted into the emboss portion of the flexible film container, reducing movement and deformation, and allowing for easier electrolyte injection and holding without increasing the battery size or complicating the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the outer peripheral portions of separators are curved or bent to be contained in the emboss portion, then the battery electrode assembly is contained in the exterior container, but the manufacturing step becomes complicated and the region for containing electrolyte becomes smaller

Engineering Contradiction:

Improvecontainment of battery electrode assemblyVSAvoidmanufacturing step complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts only the corner portions of the battery electrode assembly that need to be contained, rather than curving the entire outer peripheral portions. By taking out and folding only the four corners, the solution achieves containment while minimizing manufacturing complexity and preserving electrolyte space.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention segments the containment requirement into discrete corner portions rather than treating the entire outer periphery as a single unit. Each corner is folded independently, which simplifies the manufacturing process compared to curving the entire perimeter and maintains more electrolyte space.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the outer peripheral portions of separators are curved or bent, then the battery electrode assembly is contained in the emboss portion, but smooth electrolyte injection becomes difficult

Engineering Contradiction:

Improvecontainment of battery electrode assemblyVSAvoidelectrolyte injection smoothness

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The invention extracts only the necessary corner portions for containment, leaving the majority of the separator structure flat and unobstructed. This extraction approach ensures smooth electrolyte injection while achieving the required containment.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of curving the entire outer periphery (excessive action), the invention applies the curving action only to the four corner portions (partial action). This partial application of the curving action is sufficient for containment while minimizing interference with electrolyte injection.

Inventive Principle:

Principle #16Partial or excessive action

3Weight of moving object

If the exterior container is formed of flexible laminate films, then the battery can be lightweight, but mechanical strength becomes weak and damage to battery electrode assembly may occur

Engineering Contradiction:

Improvebattery weightVSAvoidmechanical strength of exterior container

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The invention uses flexible laminate films for the exterior container to maintain lightweight properties, and compensates for the weak mechanical strength by implementing the corner folding mechanism that prevents battery electrode assembly movement and potential damage.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The corner folding creates a beforehand cushioning effect by providing a mechanical constraint that prevents excessive movement of the battery electrode assembly, thereby protecting it from damage despite the weak mechanical strength of the flexible container.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS10454129B2Secondary battery

Publication Date: 2019.10.22 ENVISION AESC ENERGY DEVICES LTD

AI summary

Secondary battery 1 includes: battery electrode assembly 5 that has a quadrangular planar shape, and includes a positive electrode and a negative electrode laminated with a separator interposed therebetween; and an exterior container that is formed of flexible films 7, and contains battery electrode assembly 5. The exterior container has recessed emboss portion 8 that contains battery electrode assembly 5 therein. Four corners 4a of an outer peripheral portion of battery electrode assembly 5 are either folded to be contained inside emboss portion 8, or inserted between flexible films 7 outside emboss portion 8. A length of at least one side among four sides forming the quadrangular planar shape of battery electrode assembly 5 is shorter than an inner dimension of emboss portion 8 in the direction in which the one side extends.