Laser Welded Battery Electrode Tab Spiral Marks

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Solution Overview

Problem

Lithium ion batteries face short circuits due to sharp needle-shaped welding protrusions formed by ultrasonic welding, leading to safety and reliability issues.

Innovation Solution

Laser welding is used to create a battery design with spiral weld marks on the electrode sheet and tab, forming a larger contact area with the separator, preventing piercing and reducing the risk of short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ultrasonic welding is used to join electrode sheet and electrode tab, then welding efficiency is improved, but sharp needle-shaped welding protrusions are formed that can pierce the battery separator causing short circuits

Engineering Contradiction:

Improvewelding efficiencyVSAvoidshort circuit prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces ultrasonic welding (mechanical vibration-based welding) with laser welding (optical energy-based welding). This substitution eliminates the formation of sharp needle-shaped protrusions that occur with ultrasonic welding, while maintaining effective welding of the electrode tab to the current collector. The laser welding process creates a different weld morphology that does not pose a piercing risk to the battery separator.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the welding process parameters by switching from ultrasonic vibration parameters to laser energy parameters (such as laser power, scanning speed, and focal position). This parameter change fundamentally alters the welding mechanism and the resulting weld structure, producing a surface that is safe for battery separator contact while maintaining welding integrity.

Inventive Principle:

Principle #35Parameter changes

2Speed

If ultrasonic welding is used, then welding speed is improved, but welding head abrasion occurs requiring frequent replacements

Engineering Contradiction:

Improvewelding speedVSAvoidwelding head replacement frequency

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical contact-based ultrasonic welding system with a non-contact laser welding system. This eliminates the physical welding head that undergoes abrasion during ultrasonic welding, thereby removing the need for frequent welding head replacements while maintaining high welding speed through the rapid energy delivery of laser technology.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If laser welding is used to create spiral weld marks, then contact area with separator is increased preventing piercing, but welding process complexity increases

Engineering Contradiction:

Improveseparator piercing preventionVSAvoidwelding process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs spiral (curved) weld marks instead of linear weld patterns. The spiral geometry increases the contact area between the weld and the battery separator, distributing pressure more evenly and preventing localized piercing. While the spiral pattern adds some complexity to the welding path, it is efficiently achieved through automated laser scanning programs without requiring complex additional equipment.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 enhances the safety and reliability of lithium ion batteries by preventing short circuits and reducing the need for frequent welding head replacements, maintaining the flatness of the electrode tab and improving battery quality.

Implementation Method 1

the electrode tab and the electrode sheet are formed into an integral structure by laser welding

Methodology Applied

Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentUS11450932B2Battery, preparation method thereof and electric device

Publication Date: 2022.09.20 ZHUHAI COSMX BATTERY CO LTD

AI summary

The present disclosure provides a battery, a preparation method thereof and an electric device. The battery includes a housing and an accommodated battery cell including electrode sheets and electrode tabs, where the electrode sheet includes a current collector, and the current collector is coated with an active material layer, the current collector includes a coating area coated with the active material layer and an empty foil area not coated with the active material layer, one end of the electrode tab is overlapped with the empty foil area, and the electrode tab and the electrode sheet are formed into an integral structure by laser welding; a surface of the empty foil area facing away from the electrode tab has a plurality of spiral weld marks arranged at intervals; and a surface of the electrode tab facing away from the empty foil area has no weld marks.