Battery Module Bus Bar Structure for Visible Multi-Tab Laser Welding

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Solution Overview

Problem

Conventional battery modules face challenges in efficiently connecting multiple battery cells due to unstable contact between bus bars and electrode tabs, difficulty in visual confirmation of connection states, and safety risks during laser welding, which slow down the manufacturing process and increase the risk of errors.

Innovation Solution

A battery module design featuring bus bars with openings and protrusions that allow adjacent electrode tabs to be inserted and welded simultaneously, enabling visual confirmation of connections and preventing direct laser irradiation of battery cells, thus ensuring stable and efficient electrical connections and improved production speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a U-shaped bus bar is used to connect electrode tabs, then electrical connection between battery cells is achieved, but the contact becomes unstable and welding visibility is poor

Engineering Contradiction:
Improvecontact stabilityVSAvoidwelding visibility
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The bus bar is segmented into multiple flat bars, each with a separate opening, allowing individual electrode tabs to be inserted and welded independently. This segmentation improves contact stability for each connection while maintaining welding visibility for each tab

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bus bar structure is modified to have different local characteristics: flat bars provide stable contact surfaces, while openings provide visibility and access for welding. Each local region of the bus bar is optimized for its specific function

Inventive Principle:
Principle #3Local quality

2Productivity

If one bus bar connects two electrode tabs at a time, then welding visibility is maintained, but production time increases

Engineering Contradiction:
Improveproduction speedVSAvoidconnection time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

Multiple electrode tabs are combined into a single assembly that can be welded simultaneously to one bus bar. The bus bar has multiple openings that accommodate multiple tabs, allowing parallel welding operations to reduce total connection time

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If laser welding is performed on electrode tabs, then connection speed increases, but battery cells may be directly irradiated causing safety problems

Engineering Contradiction:
Improvewelding speedVSAvoidlaser irradiation safety
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The bus bar serves as an intermediary component between the laser welding process and the battery cells. The flat bar structure with openings allows the laser to weld the electrode tabs to the bus bar while the bus bar itself shields the battery cells from direct laser irradiation

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If multiple electrode tabs are welded simultaneously, then production efficiency improves, but uniform melting of tabs becomes difficult

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidwelding uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

Each opening in the bus bar is designed with specific local characteristics optimized for its associated electrode tab. The flat bars provide uniform contact surfaces, and the openings are positioned and sized to ensure consistent laser access and welding conditions for each tab, enabling uniform melting even when welding multiple tabs simultaneously

Inventive Principle:
Principle #3Local quality

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 allows for stable and uniform welding of multiple electrode tabs at once, improving production speed and safety by preventing direct laser exposure to battery cells and facilitating clear visual confirmation of connection states, thereby enhancing the manufacturing efficiency and reducing errors.

Implementation Method 1

when performing laser welding

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 2

uniformly melting electrode tabs

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3537504B1Battery module and manufacturing method thereof
Publication Date: 2024.07.03 SK ON CO LTD
  • EP3537504B1 patent drawingFigure 1
  • EP3537504B1 patent drawingFigure 2A~2B
  • EP3537504B1 patent drawingFigure 3

AI summary

The present invention provides a battery module, which includes: a plurality of battery cells which include electrode tabs, respectively; and one or more bus bars connected to the electrode tabs for electrically connecting the plurality of battery cells with each other, wherein each of the one or more bus bars includes a plate having one or more openings formed therein, and a plurality of adjacent electrode tabs among the electrode tabs are inserted into any one of the one or more openings of the plate to be electrically connected with each other.