Composite Current Collector for Battery Tab Soldering
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Solution Overview
Problem
Lithium ion batteries face safety concerns due to breakage of current collectors during soldering of electrode tabs, which can lead to explosions or fires, especially when the metallic foils used are copper, aluminum, or nickel, and there is a need for improved safety and reduced weight.
Innovation Solution
The use of a composite current collector with an insulating layer and two conductive layers, where a first conductive connector electrically connects both layers, allowing the electrode tab to connect to either layer, reducing the risk of breakage and enhancing safety by distributing the electrical connection effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metallic foils (copper, aluminum, or nickel) are used as current collectors, then electrical conductivity is improved, but breakage occurs during soldering of electrode tabs
Solution Approach 1:
The current collector is divided into multiple layers: a base metallic foil layer for electrical conductivity and an insulating layer for mechanical strength. This segmentation allows each layer to fulfill its specific function while working together to prevent breakage during soldering.
Solution Approach 2:
The patent uses a composite current collector structure combining metallic foil (copper, aluminum, or nickel) with an insulating layer. This composite material approach provides both the electrical conductivity needed for battery operation and the mechanical strength required to prevent breakage during electrode tab soldering.
2Reliability
If metallic foils are used as current collectors, then electrical conductivity is improved, but weight increases
Solution Approach 1:
The insulating layer is applied selectively to specific regions of the current collector where mechanical support is needed, rather than covering the entire surface. This local quality approach reduces the overall weight while maintaining necessary structural integrity and electrical conductivity in critical areas.
3Reliability
If electrode tabs are soldered to current collectors, then electrical connection is improved, but breakage risk increases
Solution Approach 1:
The insulating layer acts as an intermediary between the metallic foil and the electrode tab soldering process. It provides a stable surface for soldering while protecting the underlying metallic foil from direct thermal stress and mechanical stress during the soldering operation, thereby reducing breakage risk while maintaining electrical connection.
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 reduces the risk of breakage and improves the safety of lithium ion batteries by ensuring reliable electrical connections and reducing the weight of the batteries, while maintaining their performance.
Implementation Method 1
a current collector including two opposite surfaces, an insulating layer disposed on one of the two opposite surfaces of the current collector
Implementation Method 2
a first conductive layer disposed on the other opposite surface of the insulating layer, the first conductive layer being in electrical contact with the electrode active substance layer
Data Source
AI summary
An electrode assembly includes a cathode electrode plate, an anode electrode plate, and a separator disposed between the cathode electrode plate and the anode electrode plate. At least one of the cathode electrode plate and the anode electrode plate is an electrode plate which includes a current collector and a first conductive connector. The current collector includes an insulating layer having opposite side surfaces, a first conductive layer, a second conductive layer, and two electrode active substance layers. The first conductive layer and the second conductive layer are arranged on opposite side surfaces, and the two electrode active substance layers are coated onto the first conductive layer and the second conductive layer. The first conductive connector electrically connects the first conductive layer and the second conductive layer. The electrode assembly is formed by coiling the cathode electrode plate, the separator, and the anode electrode plate.