Bus Bar Protrusion Design for Laser Welding Battery Modules
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Solution Overview
Problem
Existing methods for electrically connecting battery cells, such as ultrasonic welding, face challenges with weld quality and potential damage to cells, while laser welding requires reliable contact surfaces, limiting its application to one-to-one connections and complicating the structure of the laser welder or battery module.
Innovation Solution
A bus bar with a plate-shaped structure and protrusions projecting towards electrode leads allows for close contact and reliable laser welding without complicating the laser welder or battery module structure, enabling efficient electrical connection of multiple battery cells in series or parallel configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic welding is used to electrically connect battery cells, then the connection can be established, but the mechanical burden and friction may damage the inside of battery cells and affect weld quality
Solution Approach 1:
The patent replaces ultrasonic welding (mechanical vibration-based) with laser welding (optical energy-based). The laser beam melts and fuses the bus bar to electrode leads without mechanical contact, eliminating friction and mechanical burden that could damage battery cell internals while maintaining reliable electrical connection.
Solution Approach 2:
The patent introduces a specifically designed bus bar with protrusions as an intermediary component. The protrusions ensure reliable laser welding by providing concentrated contact points with electrode leads, enabling effective energy transfer while protecting the battery cell structure from damage.
2Object-affected harmful factors
If laser welding is used to electrically connect battery cells, then damage to cells is avoided, but reliable contact surfaces are required which limits application to one-to-one connections and complicates the laser welder or battery module structure
Solution Approach 1:
The bus bar features protrusions at specific local positions where welding is required. These protrusions concentrate the welding action to precise points, ensuring reliable contact with electrode leads while keeping the rest of the bus bar structure simple and flat, suitable for batch welding of multiple cells.
Solution Approach 2:
The bus bar is designed with multiple protrusions segmented along its length, allowing simultaneous or sequential welding to multiple electrode leads. This segmentation enables multi-point connections without requiring complex positioning mechanisms, simplifying the overall welding system.
3Ease of manufacture
If a simple flat bus bar is used for laser welding, then manufacturing is simple, but reliable close contact with electrode leads cannot be ensured for high-quality welds
Solution Approach 1:
The bus bar maintains a simple flat overall structure for easy manufacturing, but incorporates localized protrusions at welding positions. These protrusions are formed through simple stamping or bending processes, ensuring reliable close contact with electrode leads for high-quality laser welding without significantly complicating manufacturing.
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 bus bar design enhances the reliability of laser welding, improves weld quality, and simplifies the assembly process, allowing for the creation of battery modules with various electrical connections without damaging the cells, while maintaining a compact and lightweight structure.
Implementation Method 1
a protrusion projecting toward the electrode leads is formed on the bus bar at a portion thereof, which is to be welded to the electrode leads through laser irradiation
Data Source
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AI summary
Disclosed herein is a bus bar for electrically connecting electrode leads of unit modules or battery cells (unit cells) in a battery module through a coupling method employing laser welding. Each of the electrode leads and the bus bar has a plate-shaped structure and a protrusion projecting toward the electrode leads is formed on the bus bar at a portion thereof, which is to be welded to the electrode leads through laser irradiation, to allow the portion of the bus bar, which is to be welded to the electrode leads, to be brought into close contact with the electrode leads.