Pouch Battery Cell Folding Structure to Prevent Bat-Ear Deformation

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Solution Overview

Problem

Pouch-type battery cells experience morphological deformation due to residual stress during the manufacturing process, particularly at the peripheral edge portions, leading to the formation of bat-ear portions and unnecessary shape deformations.

Innovation Solution

A battery cell design where the pouch case is bent based on one edge line of a hexahedral recessed portion, minimizing residual stress by forming the recessed portion so that the bending line becomes an edge, and using a stepped mold to ensure precise folding and sealing of the pouch case surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the pouch case is bent by 180 degrees on a bending line spaced apart from the edge line of the recessed portion, then the electrode assembly can be inserted into the pouch case, but residual stress causes deformation and bat-ear portions at the peripheral edge

Engineering Contradiction:

Improveease of manufactureVSAvoidmanufacturing precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The pouch case is pre-formed with a recessed portion that has an edge line serving as the bending line. This preliminary design ensures that when bending occurs, the fold is created precisely at the edge line rather than being spaced apart from it, preventing residual stress accumulation and bat-ear portion formation while maintaining ease of manufacture

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the critical parameter of bending line position from being spaced apart from the edge line to being exactly at the edge line of the recessed portion. This parameter change eliminates the gap that causes residual stress and deformation, achieving both ease of manufacture and high manufacturing precision

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the bending line is spaced apart from the edge line of the recessed portion, then the pouch case structure can be formed, but the folded portion forms a protruding bat-ear portion due to residual stress

Engineering Contradiction:

Improvedevice complexityVSAvoidshape

Core Design Contradiction:

Device complexityVSShape

Solution Approach 1:

The recessed portion is pre-designed with its edge line positioned exactly at the intended bending line location. This preliminary configuration ensures that during the bending process, the fold occurs precisely at the edge line without creating protruding bat-ear portions, maintaining both simple device structure and accurate shape

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention utilizes the edge line of the recessed portion itself as the bending line, converting what would normally be a problematic location (where bat-ear portions form) into the precise folding location. This transforms the potential source of deformation into the solution that prevents it

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS20230275291A1Battery Cell and Manufacturing Method Thereof

Publication Date: 2023.08.31 LG ENERGY SOLUTION LTD

AI summary

A battery cell according to one embodiment of the present disclosure includes an electrode assembly including a positive electrode, a negative electrode, and a separator; and a pouch case in which a recessed portion for housing the electrode assembly is formed, wherein the pouch case is bent on the basis of at least one edge line among the edges formed by the recessed portion.