Battery Module Laser Welding Bus Bar Connection
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Solution Overview
Problem
Existing battery modules face challenges in reliably connecting multiple secondary batteries in parallel due to inadequate welding techniques, leading to potential performance deterioration, malfunction, and safety risks such as electric shorts and fires.
Innovation Solution
A battery module design that uses laser welding to couple multiple electrode leads to a single bus bar, enhancing adhesion and manufacturing ease, while allowing for the use of both ultrasonic and laser welding methods to improve welding strength and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple electrode leads are welded to a bus bar in an overlapped state using laser welding, then the manufacturing process is simplified, but the welding reliability deteriorates
Solution Approach 1:
The patent divides the welding process into two distinct stages: first welding electrode leads to intermediate bus bars individually, then welding intermediate bus bars to the main bus bar. This segmentation prevents multiple electrode leads from being welded in an overlapped state, ensuring each welding point maintains high reliability while still achieving simplified manufacturing through the intermediate connection structure.
2Strength
If ultrasonic welding is used to connect electrode leads to bus bars, then welding strength is sufficient, but manufacturing costs increase due to consumable replacement
Solution Approach 1:
The patent replaces ultrasonic welding (a mechanical vibration-based process requiring consumable tools) with laser welding (an optical-based process). By using laser welding to connect electrode leads to intermediate bus bars and then intermediate bus bars to the main bus bar, the system achieves sufficient welding strength while eliminating the need for expensive consumable replacement, thereby reducing manufacturing costs.
3Reliability
If multiple bus bars are used to connect three or more secondary batteries in parallel, then welding reliability is maintained, but device complexity increases
Solution Approach 1:
The patent introduces intermediate bus bars as mediator components between electrode leads and the main bus bar. Instead of directly connecting multiple electrode leads to a single main bus bar (which would require complex overlapping welding) or using multiple separate bus bars (increasing component count), the intermediate bus bars provide a structured intermediary connection layer that maintains welding reliability while simplifying the overall module structure and assembly process.
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 configuration ensures stronger and more reliable connections between electrode leads and bus bars, increasing design freedom and reducing manufacturing costs, thereby stabilizing the battery module's performance and safety.
Implementation Method 1
the electrode leads and the bus bar are coupled to each other by means of laser welding
Implementation Method 2
when a plurality of secondary batteries, for example three or more secondary batteries, are connected in parallel, ultrasonic welding is frequently used
Data Source
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AI summary
Disclosed are a battery module and a battery pack including the same, in which laser welding can be used for coupling three or more electrode leads to a single bus bar, thereby enhancing adhesion and improving the ease of a manufacturing process. The battery module includes: a plurality of secondary batteries, each including an electrode assembly, a case and an electrode lead; and a terminal bus bar having a plate-like coupling unit, wherein electrode leads of the same polarity provided in the three or more secondary batteries are coupled to the coupling unit, two or more electrode leads stacked to each other are in contact with one end of the coupling unit, and the other one or more electrode leads are in contact with the other end of the coupling unit.