Swaged Busbar Joint Layout for Stable Dissimilar-Metal Connections

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Solution Overview

Problem

Existing busbar technologies face issues with fragile intermetallic compounds forming during dissimilar metal joining, leading to unstable connections and increased weight and volume due to the use of rivets, which reduces energy density in battery packs.

Innovation Solution

A busbar design incorporating swaged joints and metal joints that maintain intimate contact under external forces, eliminating the need for rivets and reducing intermetallic compound formation, with the metal joints disposed inwardly to enhance stability and the swaged joints positioned for increased strength and gas/heat escape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dissimilar metals are joined by laser fusion, then a metal fused portion is formed, but fragile intermetallic compounds are generated leading to connection instability

Engineering Contradiction:
Improveconnection stabilityVSAvoidintermetallic compound formation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The connection structure is segmented into three distinct zones: a swaged joint portion providing mechanical interlocking, a metal fused portion providing metallurgical bonding, and an intermediate transition zone. This segmentation allows each zone to perform its specific function optimally while reducing the formation of harmful intermetallic compounds by controlling the welding parameters in the intermediate zone.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention employs a composite connection structure combining two different joining methods: swaging (mechanical deformation) and laser fusion (metallurgical bonding). The swaged joint portion uses plastic deformation to create a mechanically interlocked structure, while the metal fused portion provides strong metallurgical bonding. This composite approach leverages the advantages of both methods while mitigating their individual disadvantages.

Inventive Principle:
Principle #40Composite materials

2Strength

If rivets are used to join metallic members, then connection strength is improved, but weight and volume of the battery pack increase

Engineering Contradiction:
Improveconnection strengthVSAvoidbattery pack weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The invention merges the joining function and the conductive function into a single integrated busbar structure. The busbar itself is formed by joining the first and second metallic members through swaged and metal fused joints, eliminating the need for separate rivets or fasteners. This integration maintains connection strength while reducing the overall weight and volume of the battery pack.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention extracts and eliminates the rivet component from the battery pack assembly. By using the busbar's own structure to provide both mechanical support and electrical conduction, the separate riveting operation and associated hardware are removed, directly reducing weight and volume while maintaining connection integrity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If rivets are used to join metallic members, then connection strength is improved, but volume of the battery pack increases

Engineering Contradiction:
Improveconnection strengthVSAvoidbattery pack volume
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The invention merges the joining function and the conductive function into a single integrated busbar structure. The busbar itself is formed by joining the first and second metallic members through swaged and metal fused joints, eliminating the need for separate rivets or fasteners. This integration maintains connection strength while reducing the overall weight and volume of the battery pack.

Inventive Principle:
Principle #5Merging (Combining)

4Strength

If multiple joints are formed at the ends of rectangular plate portions, then connection strength is increased, but gas and heat escape during welding becomes difficult

Engineering Contradiction:
Improveconnection strengthVSAvoidgas and heat accumulation
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The invention applies different joint configurations to different regions of the busbar. The swaged joint portions are positioned at the ends of the rectangular plate portions where high mechanical strength is required, while the metal fused portion is positioned in the intermediate region where heat and gas escape pathways are more accessible. This local differentiation allows each region to optimize for its specific functional requirements.

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

The busbar design achieves high conduction reliability and prevents energy density reduction by maintaining stable connections under vibrations and impacts, while eliminating the need for rivets and reducing intermetallic compound formation, thus enhancing the reliability and efficiency of battery packs.

Implementation Method 1

a swaged joint formed by plastically deforming the first plate portion of the first metallic member and the second plate portion of the second metallic member such that the first plate portion and the second plate portion are swaged together

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

a metal joint formed by metal-joining the first plate portion of the first metallic member to the second plate portion of the second metallic member

Methodology Applied
Scientific EffectMetal joining: Welding

Data Source

PatentEP4270618A1Busbar and battery pack including the same
Publication Date: 2023.11.01 PRIME PLANET ENERGY & SOLUTIONS INC
  • EP4270618A1 patent drawingFigure 1~2
  • EP4270618A1 patent drawingFigure 3~4
  • EP4270618A1 patent drawing

AI summary

A busbar (20) disclosed herein includes: a first metallic member (21) including a first plate portion (21b1); a second metallic member (22) including a second plate portion; a swaged joint (23) formed by plastically deforming the first plate portion (21b1) of the first metallic member (21) and the second plate portion of the second metallic member (22) such that the first plate portion (21b1) and the second plate portion are swaged together; and a metal joint (24) formed by metal-joining the first plate portion (21b1) of the first metallic member (21) to the second plate portion of the second metallic member (22).