Protrusion Current Block for Battery Resistance Welding
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Solution Overview
Problem
Conventional welding methods for lithium-ion secondary batteries, such as laser, ultrasonic, and resistance welding, face challenges in reducing internal resistance and preventing spattering and internal short circuits due to the high thermal conductivity and reflectivity of aluminum and copper alloys, requiring complex equipment and high energy input.
Innovation Solution
A current carrying block with protrusions on opposing faces is used for resistance welding, concentrating current to generate heat stably and reduce internal resistance, while an insulating seal material captures spattered particles to prevent damage and internal short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser welding method is used, then welding can be performed on aluminum and copper alloys, but high-energy laser beam is required due to high reflectivity of about 90%, and spattering occurs
Solution Approach 1:
The patent replaces the laser welding method with a resistance welding method. Instead of using a high-energy laser beam that suffers from high reflectivity issues, the invention uses electrical current to generate heat directly at the welding interface through the natural contact resistance between the electrode substrate and collector member, eliminating the need for high-energy laser beams and reducing spattering
Solution Approach 2:
The patent changes the welding parameter from optical energy (laser) to electrical energy (current). By applying resistance welding with controlled current and pressure, the method achieves reliable welding of aluminum and copper alloys without requiring high-energy input, as the heat is generated locally at the contact interface rather than being delivered as high-intensity optical energy that is largely reflected
2Reliability
If ultrasonic welding method is used, then welding can be performed on aluminum and copper alloys, but large amount of energy is required due to large thermal conductivity, and active material may fall off
Solution Approach 1:
The patent replaces ultrasonic welding with resistance welding. Instead of using ultrasonic vibration that requires large energy input and may cause active material to fall off, the invention uses electrical current to generate heat directly at the welding interface through contact resistance, achieving reliable welding with lower energy consumption and without disturbing the active material
Solution Approach 2:
The patent changes the welding mechanism from mechanical vibration (ultrasonic) to electrical heating (resistance welding). By controlling the current and pressure parameters, the method generates heat locally at the contact interface without requiring large amounts of energy or mechanical vibration that could dislodge active material
3Reliability
If resistance welding method is used with conventional electrode rods, then welding can be performed on aluminum and copper alloys, but electrode rods and collector member may be melted together, and melting or spark occurs at locations other than welded part
Solution Approach 1:
The patent introduces a current carrying block with a protrusion that segments the current path and concentrates it at a specific location. The protrusion design ensures that current flows through a defined path, localizing the heat generation to the intended welding interface and preventing melting or spattering at other locations
Solution Approach 2:
The patent applies local quality by designing the current carrying block with a protrusion that concentrates current at a specific point. This creates localized heat generation only at the welding interface between the electrode substrate and collector member, while other areas remain unaffected, preventing unwanted melting or spattering
4Reliability
If multiple substrate exposed portions are stacked and welded, then electrical current can be collected effectively, but welding time increases and productivity decreases
Solution Approach 1:
The patent merges multiple welding operations into a single step by using the current carrying block with protrusions that contact multiple substrate exposed portions simultaneously. The block is pressed down to weld all stacked substrates to the collector member in one action, eliminating the need for sequential welding and significantly improving productivity
Solution Approach 2:
The current carrying block serves multiple functions: it concentrates current, localizes heat generation, and simultaneously welds multiple substrate exposed portions. This multi-functional design allows effective current collection from stacked substrates while maintaining high welding speed and productivity
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 enables reliable, high-quality resistance welding of lithium-ion battery electrodes in a single step with reduced internal resistance and minimized spattering, improving productivity and battery performance.
Implementation Method 1
concentrating current to generate heat stably and reduce internal resistance
Implementation Method 2
an insulating seal material captures spattered particles to prevent damage and internal short circuits
Data Source
AI summary
In a sealed battery, a metal current carrying block 24A having a protrusion 24b on each of the two opposing faces is placed between positive or negative electrode substrate exposed portions that are divided into two so as to bring the protrusion 24b on each of the two opposing faces into contact with the positive or negative electrode substrate exposed portions that are stacked, a pair of electrodes 31 and 32 for resistance welding are brought into contact with positive electrode collector members 16 or negative electrode collector members that are each placed on the outermost surfaces of the positive electrode substrate exposed portions 14 or negative electrode substrate exposed portions, and resistance welding is performed with pressure applied between the pair of electrodes 31 and 32 for resistance welding.