Stainless Steel Pouch Battery Case for Deep Draw Moldability

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Solution Overview

Problem

Pouch-type secondary batteries using stainless steel as a gas barrier layer face moldability issues, leading to insufficient forming depth and potential rupture, limiting cell energy density.

Innovation Solution

A pouch-type battery case design that includes a pouch film laminate with specific parameters, utilizing stainless steel as the gas barrier layer, where the thickness of the gas barrier layer, cup part depth, and curvature radii are optimized to satisfy the equation 0.01 ≤ D / (A - (R_P + R_D + C), ensuring adequate moldability and durability under high temperature and pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If stainless steel is applied to the gas barrier layer to prevent deformation under high temperature and pressure, then durability is improved, but moldability deteriorates

Engineering Contradiction:
Improvedurability under high temperature and pressureVSAvoidmoldability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by optimizing the thickness of the stainless steel gas barrier layer and the forming depth of the cup part within specific numerical ranges. By controlling these parameters, the patent achieves sufficient moldability while maintaining the durability benefits of stainless steel under high temperature and pressure conditions.

Inventive Principle:
Principle #35Parameter changes

2Strength

If high-strength material such as stainless steel is used instead of aluminum, then resistance to high temperature and pressure is improved, but forming depth becomes insufficient

Engineering Contradiction:
Improveresistance to high temperature and pressureVSAvoidforming depth
Core Design Contradiction:
StrengthVSLength of stationary object

Solution Approach 1:

The patent resolves this contradiction by establishing specific numerical ranges for the thickness of the stainless steel gas barrier layer and the forming depth of the cup part. By controlling these parameters, the patent achieves sufficient forming depth while maintaining the high strength and temperature/pressure resistance of stainless steel.

Inventive Principle:
Principle #35Parameter changes

3Strength

If high-strength material such as stainless steel is used instead of aluminum, then resistance to high temperature and pressure is improved, but pouch rupture occurs

Engineering Contradiction:
Improveresistance to high temperature and pressureVSAvoidpouch integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent prevents pouch rupture by controlling the thickness of the stainless steel gas barrier layer and the forming depth of the cup part within specific numerical ranges. This parameter optimization ensures that the pouch maintains its integrity and does not rupture during the forming process, while still benefiting from the high strength and temperature/pressure resistance of stainless steel.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4641781A1Pouch-type battery case and pouch-type secondary battery
Publication Date: 2025.10.29 LG ENERGY SOLUTION LTD
  • EP4641781A1 patent drawingFigure 1
  • EP4641781A1 patent drawingFigure 2
  • EP4641781A1 patent drawing

AI summary

Disclosed herein is a pouch-type battery case including a pouch film laminate. A cup part can include a bottom surface and a side surface, and a flat part disposed to surround the cup part. The side surface can include a first curved portion, a planar portion, and a second curved portion, the pouch film laminate can include a base material layer, a sealant layer and gas barrier layer disposed therebetween. The pouch-type battery case is configured to satisfy Equation 1 : 0.01≤D/A−RP+RD+C where D is the gas barrier layer thickness, A is a vertical depth of the cup part, RP is a curvature radius of the first curved portion between the bottom surface and the flat part, RD is a curvature radius of the second curved portion between the planar portion and the flat part, and C is a horizontal length of the planar portion.