Battery Case Welding Orientation for Spatter Prevention

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Solution Overview

Problem

The existing methods for manufacturing batteries, particularly lithium-ion secondary batteries, face challenges in preventing metallic foreign objects such as spatters and powders from penetrating into the battery case during the welding process, which can lead to internal short circuits and battery failure.

Innovation Solution

A manufacturing method and system where the battery case is sandwiched by a pressing jig with the opening facing downward to prevent foreign objects from entering, and the welding is performed with the terminal facing upward to avoid spatter accumulation, using a magnetic cap attachment to secure the nonaqueous electrolyte inlet and employing a cleaning device to maintain the jig's cleanliness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the battery case is fixed by a jig during welding, then the welding position is stabilized, but metallic foreign objects (spatters, powders) may accumulate on the jig and penetrate into the battery case

Engineering Contradiction:

Improvewelding position stabilityVSAvoidmetallic foreign object penetration

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional welding orientation by positioning the battery case opening facing downward during welding, rather than the traditional upward orientation. This inversion prevents metallic foreign objects generated during welding from falling into the battery case, while still maintaining stable positioning through the jig. The inverting mechanism resolves the contradiction by changing the spatial relationship between the welding zone and the battery case interior.

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of manufacture

If the battery case and lid are welded with the opening facing upward, then spatter generation is normal, but spatters may fall into the battery case causing internal short circuits

Engineering Contradiction:

Improvewelding accessibilityVSAvoidbattery safety

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent inverts the welding orientation from the conventional upward-facing opening to a downward-facing opening. This allows welding to proceed with good accessibility while preventing spatters from falling into the battery case, thereby maintaining manufacturing ease while improving battery safety and reliability.

Inventive Principle:

Principle #13The other way round (Inversion)

3Productivity

If the jig is repeatedly used for fixing the battery case, then production efficiency is maintained, but spatters and metallic powders accumulate on the jig increasing contamination risk

Engineering Contradiction:

Improvejig reuse efficiencyVSAvoidspatter and powder accumulation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

By inverting the battery case orientation during welding, the patent prevents spatters and metallic powders from accumulating on the jig in the first place, as they fall away from the jig rather than adhering to it. This maintains high productivity through repeated jig usage while minimizing contamination accumulation.

Inventive Principle:

Principle #13The other way round (Inversion)

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 approach effectively prevents metallic foreign objects from entering the battery case, reducing the risk of short circuits and ensuring higher quality welds while allowing for efficient reuse of the manufacturing system components.

Implementation Method 1

sandwiching the battery case by a pressing jig in a state where the opening faces downward to close a gap between the battery case and the lid

Methodology Applied

Scientific EffectMechanical Pressure: Pressure Increase

Implementation Method 2

joining the battery case and the lid with each other by laser welding

Methodology Applied

Scientific EffectLaser Welding: Laser Beam Welding

Implementation Method 3

When joining a battery case and a lid to each other by welding, a spatter is generated

Methodology Applied

Scientific EffectSpatter Generation: Electric Arc

Data Source

PatentUS11177521B2Manufacturing method of battery and battery manufacturing system

Publication Date: 2021.11.16 TOYOTA JIDOSHA KK

AI summary

A manufacturing method includes the steps of: preparing a battery case having an opening; fabricating an assembly by inserting a wound electrode body and a lid which includes a terminal connected to the wound electrode body and which closes the opening into the battery case; sandwiching the battery case by a pressing jig in a state where the opening faces downward to close a gap between the battery case and the lid; disposing the assembly so that the terminal faces upward by inverting the assembly in a state where the battery case is sandwiched by the pressing jig; and welding the lid and the battery case to each other in a state where the terminal faces upward and the battery case is sandwiched by the pressing jig.