Dual-Thickness Bus Bar Structure for Battery Module Assembly

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Solution Overview

Problem

The challenge in existing battery modules is the difficulty in fixing conductive members to a bus bar due to displacement of relative positions, which affects assembly workability when multiple battery cells are connected in parallel.

Innovation Solution

A battery module design featuring a first bus bar with a deformable thickness acting as a thermal fuse and a second bus bar with a larger thickness, where the first bus bar is connected to electrode terminals and the second bus bar is non-contact, allowing for improved assembly by absorbing positional variations and ensuring reliable electrical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single bus bar is used to connect conductive members to battery cells, then the structure is simple, but assembly workability deteriorates when relative positions are displaced

Engineering Contradiction:
Improvebus bar structureVSAvoidassembly workability
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The bus bar is divided into a first bus bar (thin, deformable) and a second bus bar (thick, rigid), where each segment serves a different function. The first bus bar connects to electrode terminals and absorbs positional variations through deformation, while the second bus bar provides stable electrical connection without contacting the terminals directly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first bus bar is designed with deformable characteristics to dynamically adapt to positional variations between the bus bar and conductive members during assembly. This dynamic flexibility compensates for misalignment without requiring precise positioning, thereby improving assembly workability.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the bus bar thickness is increased to reduce electrical resistance, then electrical conductivity improves, but the ability to absorb positional variations deteriorates

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidpositional variation absorption
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The bus bar system is segmented into two parts with different thicknesses: the first bus bar (thin) that contacts electrode terminals and absorbs positional variations, and the second bus bar (thick) that provides low electrical resistance for stable current flow. This segmentation allows each part to optimize its specific function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the bus bar system have different local qualities: the first bus bar has small thickness for flexibility and adaptability to positional variations, while the second bus bar has large thickness for low electrical resistance. Each local region is optimized for its specific functional requirement.

Inventive Principle:
Principle #3Local quality

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 configuration enhances assembly workability and reliability by allowing the first bus bar to deform and absorb positional shifts, while the second bus bar maintains low electrical resistance and safety through thermal management.

Implementation Method 1

a first bus bar having a deformable first thickness and the first thickness configured to cause the first bus bar to melt when a large current flows, the first bus bar thus being arranged as a thermal fuse

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3780150B1Battery module, vehicle provided with same, and bus bar
Publication Date: 2025.10.01 SANYO ELECTRIC CO LTD
  • EP3780150B1 patent drawingFigure 1
  • EP3780150B1 patent drawingFigure 2
  • EP3780150B1 patent drawingFigure 3

AI summary

To provide a battery module including a bus bar capable of handling a large current, the battery module includes a plurality of battery cells each including an electrode terminal (2), and a bus bar that connects respective electrode terminals (2) of adjacent battery cells in a state where the plurality of battery cells are stacked, wherein the bus bar includes a first bus bar having a first thickness, and a second bus bar having a second thickness larger than the first thickness, the first bus bar is connected to the respective electrode terminals (2) of the adjacent battery cells, and the second bus bar is in non-contact with electrode terminals (2) of the battery cells.