Secondary Battery Collector Rough Surface Welding

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Solution Overview

Problem

Existing secondary batteries for electric vehicles and hybrid electric vehicles face challenges in achieving high energy density and reliable connection between terminals and collectors, leading to potential internal short-circuits due to sputters and burrs.

Innovation Solution

A method of manufacturing secondary batteries involves creating a rough surface portion on the collector with increased surface roughness, allowing for efficient welding with an energy ray to connect the terminal and collector, thereby enhancing reliability and preventing internal short-circuits by suppressing sputters and burrs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If welding is performed by projecting an energy ray onto a smooth collector surface, then the welding process is simple, but the connection reliability between terminal and collector is insufficient due to sputters and burrs

Engineering Contradiction:

Improveconnection reliabilityVSAvoidcollector structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The collector is designed with a rough surface portion at the specific welding location rather than making the entire collector surface rough. This local modification improves welding reliability at the critical junction while maintaining the overall simplicity of the collector structure and other components.

Inventive Principle:

Principle #3Local quality

2Reliability

If the collector surface is made rough to improve welding reliability, then connection reliability improves, but the manufacturing process becomes more complex

Engineering Contradiction:

Improvewelding connection reliabilityVSAvoidcollector manufacturing

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The rough surface portion is formed on the collector before the welding process. This preliminary preparation ensures that when welding is performed, the rough surface immediately provides the benefits of reduced sputters and burrs, making the subsequent welding process more reliable without requiring complex real-time adjustments.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If a smooth collector surface is used, then the manufacturing process is simple, but internal short-circuits may occur due to sputters and burrs

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidinternal short-circuit risk

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The rough surface portion, which might seem to increase manufacturing complexity, actually converts the harmful effects of sputters and burrs into beneficial outcomes. The rough texture captures and contains these defects, preventing them from causing internal short-circuits, thus transforming a potential harm into a protective feature.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 method improves the connection reliability between terminals and collectors, reduces the risk of internal short-circuits, and allows for a more compact battery design with higher energy density.

Implementation Method 1

the energy ray is not easily reflected compared with other portions. Accordingly, when an energy ray is projected to the rough surface portion, the temperature of the collector increases easily

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

when an energy ray is projected to the rough surface portion, the temperature of the collector increases easily, and the collector melts easily

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

the collector melts easily. Accordingly, the collector and the terminal can be connected by welding more efficiently

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 4

the collector and the terminal can be connected by welding more efficiently, and a welded portion with a higher reliability is formed

Methodology Applied

Scientific EffectWelding: Welding

Data Source

PatentUS10938057B2Method of manufacturing secondary battery

Publication Date: 2021.03.02 SANYO ELECTRIC CO LTD

AI summary

A method of manufacturing a secondary battery including an electrode body including a positive electrode plate and a negative electrode plate, an outer package including an opening and housing the electrode body, a sealing plate sealing the opening, a negative electrode terminal attached to the sealing plate, a negative electrode tab portion provided in the negative electrode plate, and a negative electrode collector electrically connecting the negative electrode tab portion and the negative electrode terminal to each other, the method including welding a flange portion of the negative electrode terminal and the negative electrode collector together by projecting an energy ray, the negative electrode collector includes, before the welding, a rough surface portion, and in the welding, the flange portion of the negative electrode terminal and the negative electrode collector are connected by welding by projecting an energy ray onto the rough surface portion.