Wire Mesh Current Collector Rolling for Stiff Battery Electrodes
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Solution Overview
Problem
Wire mesh current collectors in battery cells exhibit low strength and stiffness due to lack of bonding between wires at mesh junctions, making them difficult to handle and resulting in poor mechanical properties, which hinders the manufacturing of high-power density battery cells for electric vehicles.
Innovation Solution
The method involves rolling wire mesh current collectors using rollers with a predetermined gap to fuse, bond, or weld the wires at mesh junctions, either through skin pass rolling or roll resistance welding, while applying current to enhance mechanical connection and stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If wire mesh current collectors are used without bonding at mesh junctions, then the structure remains flexible and easy to manufacture, but the strength and stiffness are insufficient for handling and battery cell manufacturing
Solution Approach 1:
The patent applies preliminary action by bonding the mesh junctions before the wire mesh current collector is installed in the battery cell. The rolling process with controlled gap and applied current is performed in advance to create the necessary mechanical strength and stiffness, ensuring the structure can be properly handled and assembled without failure during subsequent manufacturing steps.
Solution Approach 2:
The patent changes the physical state and mechanical properties of the wire mesh by applying electrical current during the rolling process. This parameter change (from unbonded to bonded state through resistive heating) transforms the mechanical properties of the wire mesh, increasing its strength and stiffness while maintaining manufacturing feasibility.
2Productivity
If rollers with large gap are used for rolling, then the wire mesh can pass through easily, but insufficient pressure and current density are applied to fuse or weld the wires at mesh junctions
Solution Approach 1:
The patent optimizes the gap parameter to a specific range (0.5-2 times the wire diameter) and applies electrical current as an additional parameter to achieve both productivity and bonding strength. The combination of mechanical pressure from the rollers and thermal energy from the applied current creates optimal bonding conditions without requiring excessive gap reduction that would slow production.
Solution Approach 2:
The patent replaces purely mechanical bonding (which would require very small gaps and high pressures) with a combined electro-thermal-mechanical process. The electrical current generates resistive heat that facilitates bonding, allowing larger gaps and lower rolling pressures while maintaining bonding strength, thus preserving productivity.
3Strength
If rollers with small gap are used for rolling, then sufficient pressure and current density are applied to fuse or weld the wires, but the wire mesh cannot pass through easily and manufacturing efficiency decreases
Solution Approach 1:
The patent replaces excessive mechanical pressure (required for small-gap rolling) with electrical current-induced thermal energy. This substitution allows the wire mesh to pass through rollers with moderate gaps while still achieving strong bonding through resistive heating, thereby maintaining high manufacturing efficiency.
Solution Approach 2:
The patent changes the bonding mechanism from purely mechanical (pressure-based) to electro-thermal-mechanical combined. By introducing electrical current as a bonding parameter, the process achieves strong junction bonding with moderate rolling pressure and larger gaps, optimizing both strength and productivity simultaneously.
4Ease of manufacture
If the wires at mesh junctions are not bonded or welded, then the current collector structure remains simple and lightweight, but the mechanical properties are poor and handling is difficult
Solution Approach 1:
The patent applies preliminary action by bonding the mesh junctions before the wire mesh current collector is installed in the battery cell. The rolling process with controlled gap and applied current is performed in advance to create the necessary mechanical strength and stiffness, ensuring the structure can be properly handled and assembled without failure during subsequent manufacturing steps.
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 strengthened wire mesh current collectors demonstrate increased strength and stiffness, enabling improved handling and performance in battery cell manufacturing, specifically enhancing the mechanical properties and reducing resistance, thus contributing to increased power density and efficiency in electric vehicle batteries.
Implementation Method 1
rolling the wire mesh current collector using a first roller and a second roller, wherein the first roller and the second roller are spaced by a predetermined gap
Implementation Method 2
supplying current to the first roller and the second roller to heat the wire mesh current collector to at least one of fuse, bond and weld the wires at the mesh junctions
Data Source
AI summary
A method for manufacturing a current collector for an electrode of a battery cell includes providing a wire mesh current collector including wires that have a diameter and form mesh junctions; and rolling the wire mesh current collector using a first roller and a second roller, wherein the first roller and the second roller are spaced by a predetermined gap. The predetermined gap is less than 2 times the diameter of the wires of the wire mesh current collector.