Laminated Metal Foil Resistance Welding Notch Compression
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Solution Overview
Problem
Conventional resistance welding methods for manufacturing laminated metal foils face inefficiencies due to metal scattering and electrode wear, leading to increased electrode exchange frequency and reduced production speed, especially when forming notches with raised outer peripheries.
Innovation Solution
A method involving a forming step where the notch and raised portion of the laminated metal foils are compressed in the lamination direction to prevent metal scattering and adhesion to the welding electrode, followed by resistance welding with an electrode terminal to form an elliptic nugget area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a V-shaped cutter is used to form a linear notch in laminated metal foils, then the cutter can be easily pulled out and production efficiency is improved, but the outer periphery of the notch is raised to form a raised portion that causes metal scattering and adhesion to the welding electrode
Solution Approach 1:
A forming step is introduced before resistance welding to compress the raised portion formed by the V-shaped cutter. This preliminary compression action removes the harmful raised edges that would otherwise cause metal scattering and electrode adhesion during welding, while preserving the benefits of the linear notch for easy cutter removal and sufficient nugget area.
2Reliability
If multiple small holes are formed using multiple perforating needles to increase the nugget area, then resistance welding reliability is improved, but the perforating needles become difficult to pull out after forming holes in stacked metal foils
Solution Approach 1:
Instead of using multiple perforating needles that create difficult-to-remove holes, the invention uses a single V-shaped cutter to form a linear notch. The segmented blade structure of the V-shaped cutter allows it to be easily pulled out after forming the notch, while still providing sufficient nugget area for reliable welding of multiple laminated foils.
Solution Approach 2:
The invention transitions from forming point-like holes (0D/1D) to forming a linear notch (1D extended structure). This dimensional change provides sufficient welding area for multiple laminated foils while maintaining easy remover of the cutting tool, resolving the contradiction between nugget area and tool removal difficulty.
3Quantity of substance
If the number of laminated metal foils is increased to increase battery capacity, then energy storage is improved, but the nugget area becomes insufficient for reliable resistance welding
Solution Approach 1:
The V-shaped cutter creates a linear notch that extends through multiple laminated foils, providing a sufficiently large nugget area for reliable welding of increased numbers of foils. This linear extended structure allows accommodation of more laminated layers while maintaining adequate welding surface area.
Solution Approach 2:
The forming step compresses the metal foils in the lamination direction, changing the density and contact pressure parameters. This compression ensures sufficient nugget area and improves welding reliability even when the number of laminated foils is increased for higher battery capacity.
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 reduces metal scattering and electrode wear, enhancing production efficiency by decreasing the frequency of electrode exchanges and ensuring a sufficient nugget area even with smaller weld sites, thus improving the manufacturing process.
Implementation Method 1
resistance welding is performed after, using a perforating needle, a small hole is formed in laminated aluminum foils constituting a positive electrode foil
Implementation Method 2
a welding electrode is brought into contact with a metallic welding material, to cause large current to flow while applying pressure, thereby forming a nugget (alloy layer) using resistance heat generation of the metal
Implementation Method 3
a first step of, by a cutter having a vertical sectional shape that is substantially a V shape, forming, at a weld site of laminated metal foils, a notch penetrating along the lamination direction
Data Source
Figure 1A~2
Figure 3~5
Figure 6~7
AI summary
The method includes: a first step of forming, at a weld site of laminated layers of a metal foil, using a cutter having a longitudinal cross-sectional shape of a substantially V shape, a notch penetrating the laminated metal foil along a lamination direction and having a linear shape in a plan view, to cause the laminated layers of the metal foil closely contact each other in the lamination direction at an end of the notch; a second step of bringing a welding electrode into pressure contact with the weld site and then energizing the weld site via the welding electrode to perform resistance welding, and a forming step, performed between the first and second steps, of crushing the notch and a raised portion around the notch, to form a recess to thereby compress the notch and the raised portion in the lamination direction.