Current Collector Thermal Sealing on Battery Separators
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Solution Overview
Problem
Conventional methods for creating an electrical connection between a current collector and a conductive strip deposited on a polymer separator in electrochemical systems, such as lithium-ion batteries, are inadequate due to difficulties in laser or ultrasonic welding and the risk of degrading the separator, especially with polyolefin-based materials.
Innovation Solution
A thermal sealing method using an electrically conductive hot-melt polymer, such as a polypropylene or polyethylene-based compound with carbon fillers, is employed to securely connect the conductive strip to the current collector, ensuring electrical conductivity without damaging the separator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser or ultrasonic welding is used to create an electrical connection between the current collector and conductive strip, then electrical connection is achieved, but the separator is degraded
Solution Approach 1:
The patent introduces a hot-melt polymer adhesive as an intermediary material between the current collector and the conductive strip. This adhesive layer enables electrical connection through its conductive properties while avoiding the direct application of laser or ultrasonic energy to the separator, thus preventing separator degradation while maintaining reliable electrical connection.
Solution Approach 2:
The patent replaces the mechanical welding process (laser or ultrasonic welding) with a thermal bonding process using hot-melt polymer. This substitution eliminates the need for high-energy beams that cause separator degradation, while still achieving secure mechanical and electrical connection through the adhesive's bonding and conductive properties.
2Reliability
If conventional welding methods are used to connect the current collector to the conductive strip, then electrical connection is established, but manufacturing complexity increases
Solution Approach 1:
The patent changes the connection method from high-energy welding parameters (laser or ultrasonic) to lower-energy thermal bonding parameters using hot-melt polymer. This parameter change simplifies the manufacturing process by eliminating complex welding equipment and procedures, while still achieving reliable electrical connection through the adhesive's conductive properties.
Solution Approach 2:
The patent uses a hot-melt polymer adhesive that can be applied as a disposable layer between the current collector and conductive strip. This approach eliminates the need for expensive and complex welding equipment, simplifying the manufacturing process while achieving the required electrical connection reliability.
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 method provides a reliable and efficient electrical connection with lower contact resistance and improved manufacturing simplicity, maintaining the integrity of the electrochemical system's sealing and reducing manufacturing complexity.
Implementation Method 1
a tab forming a current collector thermally sealed by a hot-melt and electrically conductive polymer to the electrically conductive strip
Implementation Method 2
an electrically conductive polymer, such as a polypropylene or polyethylene-based compound with carbon fillers, is employed to securely connect the conductive strip to the current collector, ensuring electrical conductivity
Data Source
Figure 1~2
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AI summary
Current collector of an instrumentation element of an electrochemical system with a junction obtained by thermally sealing a hot-melt polymer to an electrically conductive strip supported by the electrically insulating separator of the system. The invention relates to an electrochemical system comprising: - at least one electrically insulating polymer film (1); - at least one electrically conductive strip (10) deposited directly on the electrically insulating polymer film; - at least one tab forming a current collector (7) thermally sealed to the electrically conductive strip (10) by a hot-melt and electrically conductive polymer (11).