Battery Module Bus Bar Welding Recess Design

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Solution Overview

Problem

The existing techniques for welding a bus bar to electrode leads in battery packs face challenges due to material differences between the bus bar and electrode leads, resulting in weakened welding forces and complex welding conditions, leading to potential separation and improper voltage sensing.

Innovation Solution

A battery module design where the bus bar is ultrasonically welded to a first electrode lead made of the same material, with a recessed second electrode lead allowing the bus bar to contact only the first electrode lead, ensuring stable fixation and improved welding capability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the bus bar is welded to both electrode leads made of different materials, then the electrical connection is achieved, but the welding force is weakened and welding conditions become complex

Engineering Contradiction:
Improvewelding qualityVSAvoidwelding process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the electrode lead connection structure into two separate welding zones: one for welding the bus bar to the first electrode lead, and another for welding the second electrode lead to the first electrode lead. This segmentation allows each welding operation to use optimized parameters for its specific material combination, improving welding quality while maintaining process manageability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements local quality by creating a recessed region in the second electrode lead that is smaller than the bus bar contact area. This ensures that the bus bar makes contact only with the first electrode lead in a specific localized area, allowing the welding process to be optimized for a single material interface rather than dealing with the complexity of welding to two different materials simultaneously.

Inventive Principle:
Principle #3Local quality

2Reliability

If the bus bar is welded to electrode leads with different materials, then the electrical connection is established, but the welding force becomes weak leading to potential separation

Engineering Contradiction:
Improveconnection stabilityVSAvoidwelding force
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent segments the electrical connection path so that the bus bar welds only to the first electrode lead, while the second electrode lead connects to the first electrode lead separately. This segmentation ensures that the critical bus bar connection uses optimized welding parameters for maximum strength, avoiding the weakened welding force that would result from attempting to weld to two different materials simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By creating a recessed region in the second electrode lead that is smaller than the bus bar contact area, the patent ensures that the bus bar makes contact only with the first electrode lead in a specific localized area. This local quality approach concentrates the welding force on a single material interface, maximizing welding strength and preventing connection separation.

Inventive Principle:
Principle #3Local quality

3Reliability

If the bus bar contacts both electrode leads, then the voltage sensing function is achieved, but the manufacturing time and costs increase

Engineering Contradiction:
Improvevoltage sensing accuracyVSAvoidmanufacturing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the contact areas by creating a recessed region in the second electrode lead that is smaller than the bus bar contact area. This segmentation allows the bus bar to contact only the first electrode lead in a defined area, simplifying the welding process to a single material interface and reducing manufacturing complexity, time, and costs while maintaining voltage sensing functionality through the first electrode lead connection.

Inventive Principle:
Principle #1Segmentation

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 design facilitates easy and stable welding of the bus bar to electrode leads, reducing manufacturing time and costs, while ensuring reliable voltage sensing and preventing bus bar separation, thus enhancing the performance and reliability of battery packs.

Implementation Method 1

the bus bar and the first electrode lead are welded by means of ultrasonic welding

Methodology Applied
Scientific EffectUltrasonic welding: Ultrasonic Vibration

Data Source

PatentEP3154108B1Battery module and battery pack including same
Publication Date: 2019.09.04 LG CHEM LTD
  • EP3154108B1 patent drawingFigure 1~2
  • EP3154108B1 patent drawingFigure 3
  • EP3154108B1 patent drawingFigure 4~5

AI summary

Disclosed is a battery module which may ensure improved welding and fixation power when welding a bus bar to a coupled portion of two or more electrode leads by means of ultrasonic welding. The battery module includes a first electrode lead, a second electrode lead; and a bus bar coming into contact with the first electrode lead and coupled to the first electrode lead in a region where a recess region of the second electrode lead is formed below the first electrode lead.