Patterned Bus Bar Surface for Bubble-Free Battery Lead Welding

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing bonding between electrode leads of different metals and bus bars in battery modules is hindered by poor welding strength due to bubble formation at the interface, leading to reduced durability and increased risk of short circuits.

Innovation Solution

A bus bar with surface patterns oriented in specific directions to facilitate the discharge of air bubbles during welding, featuring slits and uneven structures that enhance bonding between electrode leads of different metals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a flat bus bar is used, then the manufacturing process is simple, but the current carrying capacity is insufficient due to poor contact with battery terminals

Engineering Contradiction:
Improvecurrent carrying capacityVSAvoidbus bar structure
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The bus bar incorporates a curved surface portion that corresponds to the curved surface of the battery terminal. This curvature enables better contact between the bus bar and the battery terminal, increasing the contact area and improving current carrying capacity without requiring complex internal structures

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Quantity of substance

If the bus bar surface is made rough, then the contact area with battery terminals increases, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecontact areaVSAvoidsurface roughness control
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The bus bar features a localized curved surface portion rather than a uniformly rough surface. This localized curvature provides increased contact area specifically where needed (at the battery terminal interface) while maintaining smooth surfaces elsewhere, thereby reducing overall manufacturing precision requirements

Inventive Principle:
Principle #3Local quality

3Productivity

If a large number of bus bars are stacked, then the battery module can be assembled, but alignment precision deteriorates making assembly difficult

Engineering Contradiction:
Improveassembly efficiencyVSAvoidalignment precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The curved surface portion of the bus bar corresponds to the curved surface of the battery terminal, creating a natural geometric fit. This equipotential geometric relationship ensures automatic alignment when bus bars are stacked, maintaining high alignment precision even with multiple pieces and simplifying assembly operations

Inventive Principle:
Principle #12Equipotentiality

Data Source

PatentEP3985789B1Bus bar having surface pattern and battery module comprising same
Publication Date: 2026.04.15 LG ENERGY SOLUTION LTD
  • EP3985789B1 patent drawingFigure 1
  • EP3985789B1 patent drawingFigure 2
  • EP3985789B1 patent drawingFigure 3

AI summary

The present invention relates to a bus bar for connecting an electrode lead and a battery module comprising same. The bus bar has a surface structure having a concavity and convexity pattern aligned in one direction on a connection part with an electrode lead, and thus the weldability with the electrode lead can be enhanced.