Battery Box Connecting Element for Low-Heat Laser Welding

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Solution Overview

Problem

The existing methods for manufacturing battery boxes face challenges such as high production costs and potential warping of the base plate due to excessive heat input during welding, which can lead to premature melting and mechanical instability.

Innovation Solution

The introduction of a connecting element with a joining section designed for laser welding, allowing for a secure and economical connection to the battery box, while minimizing additional material usage and heat input, and incorporating a sheet-like lamella for enhanced mechanical stability and accessibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If connecting elements are welded to the base plate using conventional welding methods, then a mechanical connection is achieved, but the base plate warps and melts due to excessive heat input

Engineering Contradiction:
Improveconnection strengthVSAvoidbase plate deformation
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The connecting element incorporates a joining section with locally optimized geometry and material properties. This section has reduced thickness and enhanced thermal conductivity compared to the main body, concentrating heat away from the base plate during welding while maintaining connection strength at the interface.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes physical parameters of the connecting element, specifically the thickness and thermal conductivity of the joining section. By reducing thickness to 0.5-2mm and selecting materials with high thermal conductivity (≥10 W/m·K), the heat input to the base plate is controlled, preventing warping and melting while achieving sufficient connection strength.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the connecting element has a large height for sufficient screw travel, then mechanical connection stability is improved, but heat input during welding increases causing base plate melting

Engineering Contradiction:
Improvemechanical connection stabilityVSAvoidwelding heat input
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The connecting element is segmented into distinct functional sections: a connecting section with sufficient height for screw travel and a joining section with reduced height and optimized thermal properties. This segmentation allows the connecting section to provide mechanical stability while the joining section minimizes heat input during welding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the connecting element have different geometric and material properties. The joining section has reduced thickness (0.5-2mm) and high thermal conductivity, while the connecting section maintains sufficient height (5-20mm) for mechanical connection. This local differentiation resolves the contradiction between mechanical stability and heat control.

Inventive Principle:
Principle #3Local quality

3Strength

If conventional welding methods are used with filler material, then connection is achieved, but manufacturing costs significantly increase

Engineering Contradiction:
Improveweld connectionVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The invention extracts and eliminates the filler material from the welding process. By designing the joining section with optimized geometry and material composition, self-shielding gas welding or laser welding can be used without additional filler materials, reducing manufacturing complexity and cost while maintaining connection quality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The joining section is designed to perform its own joining function without requiring external filler materials. The optimized geometry and material properties of the joining section enable it to receive and distribute welding heat efficiently, allowing the welding process to be self-sufficient and eliminating the need for additional consumables.

Inventive Principle:
Principle #25Self-service

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 approach enables a more efficient, cost-effective, and reliable production process with reduced deformation of the base plate, improving mechanical stability and simplifying the manufacturing process by allowing for precise alignment and welding of connecting elements and separating plates in a single operation.

Implementation Method 1

The connecting element is joined to the base plate in the area of the joining section by welding, in particular by laser welding

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP3497733B1Battery box with connecting elements and method for producing such
Publication Date: 2024.02.14 LINDE WIEMANN
  • EP3497733B1 patent drawingFigure 1~3
  • EP3497733B1 patent drawingFigure 4~6
  • EP3497733B1 patent drawingFigure 7~8

AI summary

The invention relates to a connection element (1) for connecting a battery cell (15) of an electric vehicle (16) to a battery box (10), wherein the connection element (1) has at least one connection section (5) for connection to the battery cell (15) and is joined to the battery box (10). The problem addressed by the invention is that of being able at least largely to omit the use of additional material when the connection element is joined to the battery box and making the join to the bottom plate of the battery box better in quality and more cost-effective. The problem is solved by a connection element (1) which has at least one join section (2) for permanent connection to the battery box (10).