Rechargeable Battery Pouch Sealing for Capacity
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Solution Overview
Problem
Rechargeable batteries with spiral-wound electrode assemblies face reduced battery capacity due to the increased maximum width caused by folding sealing portions, which deteriorates space utilization.
Innovation Solution
A rechargeable battery design that includes a pouch with a sealing portion formed by thermally bonding external materials, featuring alternately folded side folding portions that protrude in the extension direction and are closely attached to the external surfaces of curved portions, allowing for increased maximum width of the electrode assembly within the pouch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealing portions are folded to form external side surfaces, then sealing is achieved, but maximum width of electrode assembly is reduced and battery capacity decreases
Solution Approach 1:
The sealing portion is configured to extend in the width direction rather than folding back on itself, utilizing the lateral dimension to achieve sealing without consuming electrode assembly width. This dimensional reorientation allows the sealing function to be accomplished perpendicular to the electrode assembly plane, preserving maximum width for active material.
Solution Approach 2:
The sealing portion is divided into multiple segments including a first sealing portion extending from one curved portion and a second sealing portion extending from the opposite curved portion. These segmented sealing portions can be independently configured to extend along the width direction, providing sealing functionality without requiring the electrode assembly to accommodate folded thickness.
2Reliability
If sealing portions are folded, then sealing is formed, but space utilization deteriorates
Solution Approach 1:
The sealing portion extends in the width direction (lateral dimension) rather than folding back in the thickness direction, thereby utilizing unused lateral space within the pouch. This dimensional shift transforms the sealing structure from a thickness-consuming fold to a width-extending configuration that better utilizes the available three-dimensional space.
Solution Approach 2:
Instead of folding the sealing portion back onto itself (conventional approach), the sealing portion is inverted to extend outward in the width direction. This inversion transforms the sealing structure from a compact fold that consumes thickness to an extended configuration that utilizes width space, thereby improving overall space utilization.
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
This design enhances battery capacity and space utilization by increasing the maximum width of the electrode assembly, preventing capacity reduction while maintaining effective sealing.
Implementation Method 1
a pouch that forms a sealing portion by thermally bonding an outer edge of a first external material and an outer edge of a second external material
Data Source
AI summary
A rechargeable battery according to an exemplary embodiment of the present invention includes: an electrode assembly formed by spirally winding a first electrode, a separator, and a second electrode; and a pouch that forms a sealing portion by thermally bonding an outer edge of a first external material and an outer edge of a second external material that receive the electrode assembly to withdraw tabs respectively connected to the first electrode and the second electrode to the outside, wherein the electrode assembly includes first curved portions that are convex at opposite sides of a first planar portion in a spiral-wound cross-section, the pouch includes a second planar portion corresponding to the first planar portion, and second curved portions that are connected to the second planar portion corresponding to the first curved portions, and the sealing portion is disposed in spaces, each set by an extension plane set in an extension direction of the first planar portion, external surfaces of the second curved portions, protruding in the extension direction, and a cross plane that is set in a direction crossing the extension direction at the end of the extension direction of the second curved portion.