Bimetallic Battery Busbar Interface for Weight-Conductance Tradeoffs

Solution Overview

Problem

Battery modules face challenges in balancing weight, cost, and conductance requirements due to the limitations of copper and aluminum busbars, necessitating a solution that leverages the advantages of both materials for improved performance and efficiency.

Innovation Solution

A bimetallic busbar assembly is introduced, combining aluminum and copper parts to provide enhanced mechanical and electrical performance, with aluminum parts electrically coupled to battery cell terminals and copper parts connected to external conductors, using methods like laser welding or brazing for efficient current transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If copper busbar is used, then conductance by volume and ampacity are improved, but weight and cost increase

Engineering Contradiction:

ImproveconductanceVSAvoidweight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The busbar structure uses different materials (aluminum and copper) in different regions to optimize local properties. The aluminum portion handles current distribution while the copper tab provides high-conductivity connection to the connector, achieving optimal conductance where needed without unnecessary weight throughout the entire busbar.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention combines aluminum and copper materials in a single busbar structure, leveraging the advantages of both materials. The aluminum body provides lightweight current distribution while the copper tab provides high conductivity for external connections, resolving the contradiction between weight and conductance.

Inventive Principle:

Principle #40Composite materials

2Weight of moving object

If aluminum busbar is used, then weight and cost are reduced, but conductance by volume and ampacity decrease

Engineering Contradiction:

ImproveweightVSAvoidconductance

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The busbar structure uses different materials (aluminum and copper) in different regions to optimize local properties. The aluminum portion handles current distribution while the copper tab provides high-conductivity connection to the connector, achieving optimal conductance where needed without unnecessary weight throughout the entire busbar.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention combines aluminum and copper materials in a single busbar structure, leveraging the advantages of both materials. The aluminum body provides lightweight current distribution while the copper tab provides high conductivity for external connections, resolving the contradiction between weight and conductance.

Inventive Principle:

Principle #40Composite materials

3Reliability

If copper busbar is used, then ampacity for given cross-section is improved, but material cost increases

Engineering Contradiction:

ImproveampacityVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The busbar structure uses different materials (aluminum and copper) in different regions to optimize local properties. The aluminum portion handles current distribution while the copper tab provides high-conductivity connection to the connector, achieving optimal conductance where needed without unnecessary weight throughout the entire busbar.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention combines aluminum and copper materials in a single busbar structure, leveraging the advantages of both materials. The aluminum body provides lightweight current distribution while the copper tab provides high conductivity for external connections, resolving the contradiction between weight and conductance.

Inventive Principle:

Principle #40Composite materials

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 bimetallic busbar assembly offers a cost-effective, space-efficient, and robust solution that improves the performance of battery modules by optimizing current flow and reducing material costs while maintaining high conductance, addressing the limitations of single-material busbars.

Implementation Method 1

The first part and the second part are electrically coupled, e.g., at an interface part, to enable transfer of current between the at least one electrical terminal and the conductor

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

using methods like laser welding or brazing for efficient current transfer

Methodology Applied

Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 3

using methods like laser welding or brazing for efficient current transfer

Methodology Applied

Scientific EffectBrazing: Brazing

Data Source

PatentUS20230318072A1Battery module with bimetallic terminal busbar and adaptable connector interface

Publication Date: 2023.10.05 RIVIAN HOLDINGS LLC

AI summary

A battery module is provided. The battery module comprises a plurality of battery cells. Each battery cell comprises a first electrical terminal and a second electrical terminal. The battery module further comprises at least one bi-metallic busbar, e.g., at least one first busbar. The at least one first busbar comprises a metallic part, e.g., a first aluminum part, electrically coupled to the first electrical terminals of a first group of the plurality of battery cells. The first busbar further comprises another metallic part, e.g., a first copper part. The first copper part comprises a first interface part electrically coupled to the first aluminum part. The first copper part comprises a first terminal part configured to be electrically coupled to a conductor external to the battery module.