Secondary Battery Case Structure With Ultrasonic Seam Joining

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Solution Overview

Problem

Conventional methods for forming a bottomed cylindrical battery case struggle with efficiently joining seams without gaps, leading to potential leakage and reduced join strength, while also resulting in significant material wastage due to the deep drawing process.

Innovation Solution

A secondary battery design featuring a bottomed cylindrical case formed by a drawing process with a cylindrical second member joined ultrasonically to the first member, ensuring secure depth and reduced material wastage, and eliminating seams at the lid join, thereby enhancing join strength and reducing leakage risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the deep drawing process is used to form a bottomed cylindrical battery case, then the case can be formed with no seams, but the material wastage increases significantly

Engineering Contradiction:

Improveseamless structureVSAvoidmaterial wastage

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The battery case is divided into two separate members: a bottomed cylindrical first member formed by deep drawing and a cylindrical second member formed by rolling. This segmentation allows the first member to provide the seamless bottom portion while the second member provides the cylindrical wall, reducing overall material wastage compared to forming the entire case by deep drawing

Inventive Principle:

Principle #1Segmentation

2Strength

If laser welding is used to join the seams of case members, then the join strength can be improved, but it is difficult to achieve firm joining with no gaps when end parts are opposed

Engineering Contradiction:

Improvejoin strengthVSAvoidalignment precision

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces laser welding with ultrasonic welding to join the first and second members. Ultrasonic welding uses mechanical vibration to create friction heat and forge the joint, which is more effective than laser welding for joining thin-walled cylindrical members and can achieve strong bonds without requiring precise end-part opposition or gap-free alignment

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The solution enables efficient and firm formation of the battery case with reduced material wastage and improved join strength, minimizing leakage and enhancing battery performance by using an ultrasonic join process that secures the cylindrical second member to the first member without gaps.

Implementation Method 1

a cylindrical second member joined ultrasonically to the first member

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

the ultrasonic join process that secures the cylindrical second member to the first member without gaps

Methodology Applied

Scientific EffectFriction heating: Viscous Heating

Data Source

PatentUS11990628B2Secondary battery

Publication Date: 2024.05.21 PRIME PLANET ENERGY & SOLUTIONS INC

AI summary

A secondary battery herein disclosed includes a case main body. The case main body accommodates a power generating element in the inside. The case main body includes a first member and a second member. The first member is bottomed cylindrical and formed from one metal plate by a drawing process. The shape of the second member is cylindrical. The second member is joined in a state fitting the second member to a cylindrical portion of the first member.