Lead Terminal Laser Welding for Stable Battery Joint Formation

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Solution Overview

Problem

Existing methods for manufacturing lead terminals for power storage devices, particularly those using percussion arc welding, suffer from issues such as irregular welded portion shapes, adherence of dissimilar metals, and limited manufacturing speed, which hinder yield and quality.

Innovation Solution

A method involving laser welding is employed, where a laser beam is applied to align and melt the end of a wire material, followed by pushing the lead wire into the molten pool to form a welded connection, ensuring precise control over the welded portion and simplifying the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If percussion arc welding is used to form the welded portion, then the yield is improved, but the reproducibility of welded portion shape deteriorates

Engineering Contradiction:
ImproveyieldVSAvoidreproducibility of welded portion shape
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical percussion arc welding system with a laser-based welding system. The laser beam provides precise energy delivery to the wire material, enabling consistent melting and welding without the mechanical variability inherent in percussion arc welding. This substitution of welding mechanism directly addresses both the yield and shape reproducibility issues.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the welding parameters by using laser beam irradiation with controlled energy input. By adjusting laser power, pulse duration, and focal position, the welding process achieves consistent molten pool formation and solidification, thereby improving the reproducibility of welded portion shapes while maintaining high yield through automated precise control.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If percussion arc welding is used to form the welded portion, then the yield is improved, but the adherence of dissimilar metals occurs

Engineering Contradiction:
ImproveyieldVSAvoidadherence of dissimilar metals
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces percussion arc welding with laser welding, which provides more controlled and localized heating. This prevents the excessive heat input and material mixing that cause dissimilar metal adherence in arc welding, while maintaining high production yield through efficient automated processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The laser beam concentrates energy precisely at the welding point on the wire material, creating a localized molten pool without excessive heat spread to adjacent areas. This localized heating prevents the widespread material mixing and dissimilar metal adherence that occurs with the broader heat zone of percussion arc welding.

Inventive Principle:
Principle #3Local quality

3Productivity

If percussion arc welding is used to form the welded portion, then the yield is improved, but the manufacturing speed deteriorates

Engineering Contradiction:
ImproveyieldVSAvoidmanufacturing speed
Core Design Contradiction:
ProductivityVSSpeed

Solution Approach 1:

The patent substitutes the relatively slow percussion arc welding process with laser welding, which offers faster heating and cooling rates. The laser beam can be rapidly positioned and activated, reducing cycle time per weld while maintaining or improving yield through consistent automated operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The laser welding process enables continuous or near-continuous welding operation with minimal interruption between cycles. The rapid heating and cooling of the laser beam allows for sustained high-speed manufacturing, improving overall manufacturing speed while the automated control system maintains high yield through consistent quality.

Inventive Principle:
Principle #20Continuity of useful action

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 improves the reproducibility of welded portion shapes, prevents adherence of dissimilar metals, and enhances manufacturing speed, resulting in higher yield and quality of lead terminals for power storage devices.

Implementation Method 1

a laser beam is applied to an end portion (100a) of the wire material (100) on the lead wire side to melt the end portion

Methodology Applied
Scientific EffectLaser heating: Laser

Data Source

PatentEP4718488A1Method for manufacturing lead terminal for power storage device, and lead terminal for power storage device
Publication Date: 2026.04.01 KOHOKU KOGYO CO LTD
  • EP4718488A1 patent drawingFigure 1
  • EP4718488A1 patent drawingFigure 2A~2D
  • EP4718488A1 patent drawingFigure 3

AI summary

Provided is a method of manufacturing a lead terminal for a power storage device, the lead terminal including: an electrode terminal (2) formed of a wire material (100) mainly containing aluminum or copper; and a lead wire (3) connected to the electrode terminal through intermediation of a welded portion (4), the method including: a first step of aligning the wire material and the lead wire in a straight line, and holding the wire material and the lead wire under a state in which a distance between an end surface (100b) of the wire material on the lead wire side and an end surface (3b) of the lead wire on the wire material side is maintained at a predetermined distance; a second step of applying, by a laser irradiation machine (400), a laser beam to an end portion (100a) of the wire material on the lead wire side to melt the end portion; and a third step of pushing one of the wire material or the lead wire toward another one of the wire material or the lead wire in an axial direction after an elapse of a predetermined time from a time point of start of irradiation with the laser beam in the second step to form the welded portion.