Battery Module Bus Bar with Segmented Metal Plates

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Solution Overview

Problem

Existing battery modules face challenges in maintaining reliable electrical connections between electrode leads and bus bars, particularly when different metal materials are used, leading to weakened welding and potential disconnection issues, especially in high-temperature applications and complex bus bar shapes.

Innovation Solution

A battery module design featuring a bus bar with multiple metal plates made of the same material as the electrode leads, coupled with a main frame of a different material, ensuring stable connections through mixed metal bonding and allowing for various shapes and efficient laser welding, thereby preventing disconnection and optimizing weight and space utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If different metal materials are used for the bus bar and electrode lead, then the electrical connection can be established, but the welding performance deteriorates and connection reliability decreases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidwelding performance
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The bus bar is designed with different metal materials at different locations: the main body uses one metal material while the connection portion uses another metal material that is compatible with the electrode lead. This local differentiation allows optimal welding performance at the connection interface while maintaining the overall structural integrity and electrical conductivity of the bus bar.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bus bar employs a composite structure combining two different metal materials. The first metal material forms the main body of the bus bar, while the second metal material is used specifically at the connection portion where it contacts the electrode lead. This composite material approach resolves the incompatibility between different metals by strategically placing compatible materials at the welding interface.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If the bus bar is manufactured using a pressing process, then the manufacturing is simplified, but it is difficult to realize complicated shapes and optimize weight

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidshape complexity
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The bus bar is divided into multiple segments or portions, each with potentially different materials or structures. The connection portion is separated as a distinct element that can be optimally designed for welding, while the main body can be designed for electrical conductivity and structural support. This segmentation allows each part to be optimized independently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the bus bar are designed with different properties: the main body may have a simpler structure optimized for manufacturing, while the connection portion has a specifically designed structure optimized for welding and electrical connection. This local differentiation enables complicated shapes where needed without compromising overall manufacturing efficiency.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the bus bar is manufactured using a casting process, then complicated shapes can be realized, but pores are generated inside making laser welding difficult

Engineering Contradiction:
Improveshape complexityVSAvoidwelding reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The bus bar is divided into a main body portion that can be cast with complicated shapes and a separate connection portion that is designed for welding. By separating the casting process from the welding-critical regions, the design allows complex overall shapes while maintaining welding reliability at the connection interface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection portion of the bus bar is designed with different material properties or structural characteristics compared to the main body. This local differentiation ensures that the welding-critical area has optimal properties for laser welding (free of pores, proper material composition) while the main body can utilize casting for complex shapes.

Inventive Principle:
Principle #3Local quality

4Power

If high temperature is generated at the electrode lead and bus bar, then high output characteristics are achieved, but the welding force weakens and shape deformation occurs

Engineering Contradiction:
Improveoutput characteristicsVSAvoidwelding force
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

The bus bar uses different metal materials at different locations to manage thermal effects. The connection portion uses a material with appropriate thermal properties for welding stability, while the main body can handle higher temperatures for power transmission. This local differentiation allows high output characteristics while maintaining welding force at the connection interface.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The combination of two different metal materials in the bus bar creates a composite structure that balances thermal performance and mechanical strength. The first metal material provides high temperature tolerance for power transmission, while the second metal material at the connection portion maintains welding force and prevents deformation under thermal stress.

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 solution enhances bonding reliability and efficiency, preventing disconnection and improving output capacity while allowing for compact and durable battery modules with enhanced space efficiency and resistance to external interference.

Implementation Method 1

when a laser welding process is performed to connect the electrode lead and the bus bar

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP3547401B1Battery module
Publication Date: 2023.07.26 LG ENERGY SOLUTION LTD
  • EP3547401B1 patent drawingFigure 1
  • EP3547401B1 patent drawingFigure 2
  • EP3547401B1 patent drawingFigure 3

AI summary

Disclosed is a battery module capable of improving electric connection between an electrode lead of a secondary battery and a bus bar. In detail, the battery module includes a plurality of pouch-type secondary batteries; and a bus bar contacted to at least two of first electrode leads and second electrode leads of the secondary batteries, wherein the bus bar includes at least two metal plates contacted and connected to at least two of the first electrode leads and the second electrode leads of at least two secondary batteries; and a main frame coupled to the metal plates, wherein at least one of the metal plates has a different kind of metal material from the main frame.