Bus Bar Connection Layout for Uniform Battery Module Resistance Welding

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Solution Overview

Problem

The existing battery modules face challenges in efficiently performing resistance welding due to narrow welding spaces and inconsistent current paths, leading to welding defects, increased manufacturing costs, and reduced durability of the battery module.

Innovation Solution

The battery module incorporates a bus bar with a unique connection portion design, featuring three protrusive connection portions with identical electric connection path lengths, allowing for uniform resistance welding even in narrow spaces and preventing short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If multiple welding points are added to the bus bar to increase bonding strength, then bonding strength is improved, but welding space becomes insufficient and welding quality becomes inconsistent

Engineering Contradiction:
Improvebonding strengthVSAvoidwelding operation
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The connection portion of the bus bar is divided into multiple connection portions (first, second, and third connection portions) that protrude in different directions. This segmentation allows welding operations to be performed at multiple locations without requiring all welding points to be accessible simultaneously, thereby maintaining welding strength while improving weldability in narrow spaces

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection portions are designed with asymmetric spatial arrangement, protruding in different directions from the body portion. This asymmetric configuration optimizes the use of available welding space and ensures that welding rod current paths have substantially equal lengths, achieving uniform welding quality across all bonding portions

Inventive Principle:
Principle #4Asymmetry

2Reliability

If welding points are positioned at different locations on the bus bar, then bonding coverage is improved, but current path length becomes inconsistent causing welding defects

Engineering Contradiction:
Improvewelding quality uniformityVSAvoidcurrent path design
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The connection portions are positioned asymmetrically in different directions, yet their spatial arrangement is specifically designed so that the welding rod current paths from the electrode terminal to each welding point have substantially equal lengths. This achieves uniform welding quality without requiring symmetric positioning

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The design controls the geometric parameters of the connection portions (lengths and directions of protrusions) to ensure that the electrical path lengths remain substantially equal. By adjusting these geometric parameters, uniform current distribution is achieved across all welding points, preventing welding defects

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the bus bar connection portion is designed with multiple protruding sections, then ease of welding is improved, but the risk of short circuit between positive and negative terminals increases

Engineering Contradiction:
Improvewelding accessibilityVSAvoidshort circuit risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The connection portion is segmented into multiple distinct connection portions that protrude in different directions. Each connection portion is designed to connect to terminals of the same polarity, and the segmentation creates natural spatial separation that prevents accidental contact between positive and negative terminals during welding operations

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insulated housing serves as an intermediary protective element that surrounds the bus bar and connection portions. This housing provides physical isolation between positive and negative connection portions, preventing short circuits while allowing welding access through designed openings

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enhances the efficiency of resistance welding and improves bonding reliability by allowing uniform current distribution across multiple welding points, reducing defects, and increasing the durability of the battery module.

Implementation Method 1

a length of an electric connection path between the welding point of the first connection portion and the welding point of the second connection portion may be identical to a length of an electric connection path between the welding point of the first connection portion and the welding point of the third connection portion

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

improved in efficiency of resistance welding and bonding reliability

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4053989B1Battery module having busbar, battery pack and vehicle
Publication Date: 2025.05.14 LG ENERGY SOLUTION LTD
  • EP4053989B1 patent drawingFigure 1
  • EP4053989B1 patent drawingFigure 2
  • EP4053989B1 patent drawingFigure 3~4

AI summary

Disclosed is a battery module improved in efficiency of resistance welding and bonding reliability. The battery module includes a plurality of secondary batteries, each having electrode terminals; a module housing having an inner space formed to accommodate the plurality of secondary batteries; and a bus bar including a body portion having a metal plate configured to electrically connect the plurality of secondary batteries to each other and a connection portion extending from the body portion to contact the electrode terminal, and each of the first connection portion, the second connection portion and the third connection portion has at least one welding point.