Laser Welding Jig for Busbar-Free Battery Cell Lead Joining

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Solution Overview

Problem

Existing battery cell assemblies require busbars for electrical connection, which increase weight and cost, and there is a need for a more efficient welding method that omits the use of metal busbars.

Innovation Solution

A laser welding jig and method that includes a protective jig positioned between adjacent battery cell leads, using a pallet and insulating block to stabilize and insulate the welding process, allowing for direct electrical connection without a busbar.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If busbars are used for electrical connection of battery cells, then reliable electrical connection is achieved, but weight and manufacturing cost increase

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidbattery pack weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent extracts and eliminates the busbar component from the battery assembly system. By directly welding leads of adjacent battery cells together, the busbar is completely removed, achieving weight reduction while maintaining electrical connection reliability through direct lead-to-lead welding joints.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the functions of the busbar and lead connections by directly welding leads of adjacent battery cells together. This integration eliminates the intermediate busbar component, creating a more compact and lighter electrical connection system while maintaining reliable current flow between cells.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If busbars are used for electrical connection, then electrical connectivity is ensured, but manufacturing cost increases

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the busbar component from the battery assembly system. By directly welding leads of adjacent battery cells together, the busbar is completely removed, achieving weight reduction while maintaining electrical connection reliability through direct lead-to-lead welding joints.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive metal busbars with a simpler, more cost-effective direct lead welding approach. The elimination of busbar materials and associated manufacturing steps significantly reduces production costs while maintaining reliable electrical connections through optimized welding processes.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Object-affected harmful factors

If protective jig is positioned between adjacent leads, then battery cell assembly is protected from welding plasma, but device complexity increases

Engineering Contradiction:
Improvewelding plasma damage protectionVSAvoidwelding jig complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent introduces a protective jig as an intermediary component positioned between adjacent battery cell leads during welding. This simple protective barrier effectively shields the battery cell assembly from welding plasma damage without requiring complex shielding systems or advanced plasma control mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective jig functions as a thin protective barrier that effectively blocks welding plasma from damaging the battery cell assembly. This simple shielding approach provides adequate protection without adding significant structural complexity or requiring厚重 protective enclosures.

Inventive Principle:
Principle #30Flexible shells and thin films

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 protects the battery cell assembly from welding plasma, ensures stable electrical connections, reduces weight and cost, and prevents short circuits, enabling efficient assembly of battery packs without busbars.

Implementation Method 1

laser welding jig applied to a battery cell assembly in which adjacent two leads are bent and welded

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP4717399A1Laser welding jig, laser welding system, and welding method using same
Publication Date: 2026.04.01 LG ENERGY SOLUTION LTD
  • EP4717399A1 patent drawingFigure 1
  • EP4717399A1 patent drawingFigure 2
  • EP4717399A1 patent drawingFigure 3

AI summary

A laser welding jig according to the present invention is applied to a battery cell assembly including a plurality of stacked battery cells and a side frame covering at least a portion of the plurality of battery cells, in which two adjacent leads are bent and welded, and the laser welding jig comprises: a pallet configured to allow the battery cell assembly to be seated thereon; and a protective jig arranged between the two adjacent leads.