Pouch Battery Case Geometry for Stainless Steel Barrier Forming
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Solution Overview
Problem
Pouch-type secondary batteries using stainless steel as a gas barrier layer face moldability issues, leading to limited forming depth and potential rupture, which restricts the number of electrode assemblies and energy density.
Innovation Solution
A pouch-type battery case design that incorporates a stainless steel gas barrier layer, with specific parameters controlling the thickness and curvature radii of its components, ensuring adequate moldability and durability under high temperature and pressure conditions.
Engineering Contradictions & Design Principles
Engineering 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 leading to limited forming depth and potential rupture
Solution Approach 1:
The pouch film laminate uses a composite structure with stainless steel as the gas barrier layer (providing durability) combined with other polymer layers (providing moldability). This composite approach allows the pouch to withstand high temperature and pressure while maintaining sufficient formability during manufacturing.
Solution Approach 2:
The patent optimizes specific parameters of the pouch cup part including curvature radius (R1, R2), depth (H), and thickness (t) to satisfy a specific mathematical relationship. By carefully controlling these geometric parameters, the pouch achieves both adequate forming depth for good moldability and sufficient structural strength for durability under elevated temperature and pressure conditions.
2Reliability
If stainless steel is applied to the gas barrier layer, then resistance to high temperature and pressure is improved, but forming depth is limited reducing energy density
Solution Approach 1:
The patent establishes specific parameter relationships for the pouch cup geometry (curvature radii R1 and R2, depth H, thickness t) that must satisfy a mathematical formula. By optimizing these parameters, sufficient forming depth is achieved despite using stainless steel, thereby enabling greater energy density while maintaining resistance to high temperature and pressure.
3Strength
If stainless steel is applied to the gas barrier layer, then mechanical strength is improved, but pouch rupture risk increases during molding
Solution Approach 1:
The patent controls specific geometric parameters of the pouch cup including curvature radii (R1, R2), depth (H), and thickness (t) to satisfy a specific mathematical relationship. This parameter optimization ensures that the pouch has sufficient flexibility during molding to prevent rupture while maintaining the mechanical strength provided by the stainless steel gas barrier layer.
Data Source
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.