Battery Module Busbar Structure for Shorter Current Paths

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional battery modules suffer from increased resistance due to the long current movement paths between electrode leads, which reduces the output of the battery module.

Innovation Solution

The battery module incorporates a busbar with concave parts recessed toward the center and protruding parts on either side, allowing electrode leads to wrap around these concave parts for a shorter current path, reducing resistance and improving output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a conventional square busbar with an open center is used, then the structure is simple and easy to manufacture, but the current movement path between electrode leads becomes long, increasing resistance and lowering output

Engineering Contradiction:
Improvebattery module outputVSAvoidbusbar structure complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The busbar structure is transformed from a conventional square shape with an open center to a circular shape with a central through-hole. This curvature change allows electrode leads to pass through the center, creating the shortest possible current movement path between positive and negative terminals, thereby minimizing resistance and maximizing power output.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The design transitions from a two-dimensional planar current path (current flowing around the perimeter of a square busbar) to a three-dimensional configuration where current flows directly through the center of the busbar via the through-hole. This dimensional change dramatically shortens the current path length and reduces resistance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of energy

If the busbar shape is changed to reduce current movement path, then resistance decreases and output improves, but the manufacturing complexity may increase

Engineering Contradiction:
Improveresistance lossVSAvoidbusbar manufacturing ease
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The busbar geometry is changed from a square cross-section with an open center to a circular cross-section with a central through-hole. This parameter change optimizes the current path length while maintaining manufacturability through standard circular hole drilling and welding processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

A central through-hole is extracted from the busbar structure, creating a void space that allows electrode leads to pass directly through the busbar center. This extraction creates the shortest possible current path while the remaining busbar material maintains sufficient cross-sectional area for current conduction.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If electrode leads are positioned to minimize current path, then resistance is reduced, but the busbar structure becomes more complex

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidbusbar and lead assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The busbar design integrates the current conduction function and the lead positioning function into a single structural element. The central through-hole serves both as a mechanical guide for lead insertion and as the optimal current path, eliminating the need for separate positioning features and simplifying the overall assembly.

Inventive Principle:
Principle #5Merging (Combining)

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 minimizes the current movement distance, thereby reducing internal resistance and enhancing the output and capacity of the battery module without increasing manufacturing costs.

Implementation Method 1

a busbar frame connected to the battery cell stack, a busbar disposed on the busbar frame, and an electrode lead extending from a battery cell of the battery cell stack and welded to the busbar

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the longer the moving distance of the current, the greater the resistance, which ultimately causes a problem that the output of the battery module is lowered

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP4203171B1Battery module and battery pack including same
Publication Date: 2025.10.15 LG ENERGY SOLUTION LTD
  • EP4203171B1 patent drawingFigure 1~2
  • EP4203171B1 patent drawingFigure 3~4
  • EP4203171B1 patent drawingFigure 5

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, a busbar disposed on the busbar frame, and an electrode lead extending from a battery cell of the battery cell stack and welded to the busbar, wherein the busbar includes at least one or more concave parts recessed toward the center of the busbar, and a protrusion part protruding in a direction opposite to the center of the busbar.