Battery Pack Laser Tab Welding with PCB Shielding Layer
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Solution Overview
Problem
Existing battery pack manufacturing processes face challenges in preventing circuit board damage during laser beam welding and ensuring accurate welding quality without additional inspection processes.
Innovation Solution
The battery pack design incorporates a protection layer on the circuit board to block laser beams and a thermochromic or resistive second layer for visual inspection of welding quality, allowing for safe and reliable welding without damaging the circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser beam welding is performed to join battery cells and protective circuit module, then welding strength and electrical connection are improved, but circuit board damage occurs due to laser penetration
Solution Approach 1:
A metal layer is introduced as an intermediary between the laser beam and the circuit board. This metal layer absorbs or reflects the laser energy, preventing it from penetrating through to damage the circuit board while still allowing the welding process to occur at the electrode tab and protective circuit module interface
Solution Approach 2:
The metal layer is pre-applied to the circuit board before the welding process. This preliminary action ensures that the protective function is in place before the harmful laser exposure occurs, preventing circuit board damage from the outset
2Measurement precision
If traditional welding inspection methods are used, then welding quality can be verified, but additional inspection processes increase manufacturing complexity and time
Solution Approach 1:
The metal layer exhibits color changes or visual characteristics that indicate welding quality. By observing the appearance, color, or reflection properties of the metal layer after welding, inspectors can directly assess welding quality without complex additional equipment or processes
Solution Approach 2:
The metal layer serves dual functions: it protects the circuit board from laser damage and simultaneously provides visual indication of welding quality. This self-service function eliminates the need for separate inspection mechanisms, reducing manufacturing complexity
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 solution effectively prevents circuit board damage during welding and enables real-time visual inspection of welding quality, enhancing operational speed and reliability.
Implementation Method 1
a protection layer provided on a surface of the circuit board, the protection layer to protect the circuit board from damage when a battery cell and the protective circuit module are welded to each other
Implementation Method 2
a thermochromic or resistive second layer for visual inspection of welding quality
Implementation Method 3
a thermochromic or resistive second layer for visual inspection of welding quality
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Disclosed is a battery pack, which can observe welding quality from its appearance while preventing a circuit board from being damaged when laser beam welding is performed in a state in which a protective circuit module and battery cells are mounted on a frame. In an example embodiment, the battery pack includes a protective circuit module including a circuit board extending in a first direction, an electrode tab coupling portion mounted on a top surface of the circuit board, and a protection layer positioned under the electrode tab coupling portion, and a battery cell including an electrode tab protruding to one end and having a polarity, and coupled to a top surface of the electrode tab coupling portion, wherein the electrode tab of the battery cell and the electrode tab coupling portion and the protection layer of the protective circuit module are stacked and coupled in a second direction perpendicular to the first direction.