Segmented Secondary Battery Enclosure for Higher Capacity Cells

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Solution Overview

Problem

Conventional pouch cells face limitations in battery capacity due to cracks in the pouch film during molding, material restrictions, and limited depth of molding, necessitating a form that improves capacity while reducing shape restrictions and moisture ingress.

Innovation Solution

A secondary battery design featuring an electrode assembly surrounded by an outer film and a cap with a connection portion, terminal portion, and busbar configuration that eliminates molding, enhances structural stability, and reduces moisture ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional pouch cells are used, then manufacturing is simple, but cracks occur in the pouch film during molding and battery capacity is limited

Engineering Contradiction:
Improvepouch film integrityVSAvoidbattery structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The battery structure is divided into two main components: an outer film that surrounds a portion of the electrode assembly and a cap that surrounds the remainder. This segmentation eliminates the need for complex molding of a single pouch film, preventing cracks while maintaining structural integrity and allowing increased battery capacity through the modular design.

Inventive Principle:
Principle #1Segmentation

2Volume of moving object

If pouch film molding depth is increased to improve battery capacity, then material properties restrict further depth increase

Engineering Contradiction:
Improvebattery capacityVSAvoidpouch film material limit
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

By dividing the enclosing structure into an outer film and a cap, the design removes the molding depth limitation inherent in single-piece pouch films. The cap can be formed separately and attached to the outer film, enabling greater battery capacity without exceeding material strength limits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The structural parameters of the battery enclosure are changed from a single molded pouch film to a composite structure of outer film and cap. This parameter change allows the battery to achieve greater volume and capacity while maintaining structural integrity, as each component can be optimized independently.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If outer film is removed to simplify manufacturing, then structural stability and moisture protection are reduced

Engineering Contradiction:
Improvemanufacturing processVSAvoidmoisture barrier
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The battery structure segments the protective functions between the outer film and cap. The outer film provides the primary moisture barrier and structural stability, while the cap provides additional protection and houses the terminal portion. This segmentation maintains reliability while simplifying manufacturing, as each component can be produced and assembled separately.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4697488A1Secondary battery, manufacturing method thereof, and battery pack
Publication Date: 2026.02.18 LG ENERGY SOLUTION LTD
  • EP4697488A1 patent drawingFigure 1
  • EP4697488A1 patent drawingFigure 2
  • EP4697488A1 patent drawingFigure 3

AI summary

The present disclosure relates to a secondary battery that has improved battery capacity while simultaneously having fewer restrictions on shape, may reduce the amount of moisture introduced from the outside, and has improved structural stability. A secondary battery according to the present disclosure may include an electrode assembly, an outer film surrounding a portion of the electrode assembly, and a cap surrounding the remainder of the electrode assembly, wherein the cap may include a connection portion coupled to the outer film, a terminal portion partially embedded in the connection portion, and an outer surface portion covering at least a portion of an outer surface of the terminal portion facing the outside of the electrode assembly.