Battery Module Busbar Welding Layout for Compact Lead Joining

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Solution Overview

Problem

Conventional battery modules face challenges in managing electrode lead connections due to increased number of leads and terraces, leading to higher welding machine specifications, welding deviations, and cost inefficiencies, particularly when forming compact structures.

Innovation Solution

The battery module employs a welding structure where electrode leads overlap with a busbar and are welded at multiple points, with varying lengths and angles, and are fixed using a jig, reducing the need for advanced welding machines and minimizing lead cutting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the number of cell terraces and battery cells is increased to achieve large capacity structure, then the energy storage capacity is improved, but the number of electrode leads increases accordingly which complicates the welding structure and increases manufacturing complexity

Engineering Contradiction:
Improveenergy storage capacityVSAvoidwelding structure complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

Multiple electrode leads are superposed and merged onto a single busbar element, allowing several leads to be welded together at one location. This consolidates multiple connection points into fewer welding positions, reducing the overall welding structure complexity while accommodating increased numbers of battery cells and terraces

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The busbar element serves multiple functions simultaneously: it acts as an electrical conductor, a structural support, and a consolidation point for multiple electrode leads. This multi-functional design allows the same component to handle increasing numbers of connections without proportionally increasing structural complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If multiple electrode leads are superposed on a busbar element to be welded, then the welding structure is simplified, but the welding machine specifications must be increased which raises manufacturing costs

Engineering Contradiction:
Improvewelding structure complexityVSAvoidwelding machine specifications
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The welding process is segmented into multiple stages or positions along the busbar element. Instead of welding all leads simultaneously at one point with high power, the welding is distributed across multiple locations, allowing the use of lower specification welding machines that can operate at reduced power levels for each individual welding position

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrode leads are arranged to overlap partially on the busbar rather than requiring complete simultaneous welding of all leads. This partial action approach allows welding to be performed on subsets of leads at different positions, reducing the peak power requirement for the welding machine while still achieving complete electrical connections

Inventive Principle:
Principle #16Partial or excessive action

3Volume of moving object

If electrode leads are arranged in a compact shape to reduce the battery module size, then the module dimensions are reduced, but the amount of electrode lead cutting increases which results in cost loss

Engineering Contradiction:
Improvebattery module sizeVSAvoidelectrode lead material loss
Core Design Contradiction:
Volume of moving objectVSLoss of substance

Solution Approach 1:

The electrode leads are pre-formed with predetermined lengths and configurations before assembly. By preparing the leads in advance with appropriate lengths for the compact arrangement, unnecessary cutting during final assembly is minimized, reducing material waste while achieving the desired compact module dimensions

Inventive Principle:
Principle #10Preliminary action

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 approach stabilizes welding quality, reduces costs, and enables a compact design by minimizing gaps between the busbar frame and battery cell stack.

Implementation Method 1

a first welding portion welded between the N electrode leads, and a second welding portion welded between N-1 electrode leads among the N electrode leads, with the electrode lead closest to the busbar and the busbar being welded

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3916825B1Battery module, battery module manufacturing method, and battery pack comprising battery module
Publication Date: 2026.04.01 LG ENERGY SOLUTION LTD
  • EP3916825B1 patent drawingFigure 1~2
  • EP3916825B1 patent drawingFigure 3~4
  • EP3916825B1 patent drawingFigure 5~6

AI summary

A battery module according to an embodiment of the present disclosure includes a battery cell stack in which a plurality of battery cells are stacked, a busbar frame connected to the battery cell stack, cell terraces each protruding from the battery cells adjacent to each other among battery cells included in the battery cell stack, and electrode leads each protruding from the cell terraces and having the same polarity, wherein the electrode leads overlap with the same busbar, and may have at least two welding points at overlapping portions of the busbar and the electrode leads.