Curved Cap Assembly for Thin Cylindrical Secondary Batteries

Solution Overview

Problem

Existing secondary batteries face challenges in maintaining high capacity and energy density while ensuring durability against forces applied during cell formation, particularly with thinner cap assemblies that are prone to deformation.

Innovation Solution

A secondary battery design featuring a cap assembly where the circumferential portion of the cap-up is half-curled in a downward direction toward a safety plate, maintaining a thinner profile while enhancing structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the cap assembly is made thinner to increase cell capacity and energy density, then the capacity and energy density are improved, but the cap assembly becomes more easily deformed by force applied during cell forming

Engineering Contradiction:

Improvecell capacityVSAvoidcap assembly durability

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The cap-up circumference flat portion is bent in a downward direction to form a cap-up circumference bent portion, creating a curved structural configuration. This curvature provides structural reinforcement to the cap assembly, enabling it to resist deformation during cell forming while maintaining a thin overall profile that preserves cell capacity and energy density.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Quantity of substance

If the cap assembly is made thinner to increase cell capacity and energy density, then the energy density is improved, but the cap assembly becomes more easily deformed by force applied during cell forming

Engineering Contradiction:

Improveenergy densityVSAvoidcap assembly durability

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The cap-up circumference flat portion is bent in a downward direction to form a cap-up circumference bent portion, creating a curved structural configuration. This curvature provides structural reinforcement to the cap assembly, enabling it to resist deformation during cell forming while maintaining a thin overall profile that preserves cell capacity and energy density.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Strength

If a cap-up is provided to prevent deformation during cell forming, then the durability is improved, but the overall thickness of the cap assembly increases

Engineering Contradiction:

Improvecap assembly durabilityVSAvoidcap assembly thickness

Core Design Contradiction:

StrengthVSLength of moving object

Solution Approach 1:

The cap-up circumference flat portion is bent in a downward direction to form a cap-up circumference bent portion, creating a curved structural configuration. This curvature provides structural reinforcement to the cap assembly, enabling it to resist deformation during cell forming while maintaining a thin overall profile that preserves cell capacity and energy density.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The cap assembly utilizes a thin-film structure with a bent portion that provides structural integrity without significant thickness increase. The bent configuration acts as a reinforcement element within the thin profile, preventing deformation during cell forming while maintaining space efficiency.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS20250062455A1Secondary battery

Publication Date: 2025.02.20 SAMSUNG SDI CO LTD

AI summary

A secondary battery includes a cylindrical can, an electrode assembly in the cylindrical can together with an electrolytic solution, and a cap assembly coupled to the top of the cylindrical can, the cap assembly including a cap-up including a cap-up circumference flat portion and a cap-up circumference bent portion bent from the cap-up circumference flat portion in a downward direction and a safety plate coupled to the cap-up circumference flat portion and the cap-up circumference bent portion.