Multilayer Current Collector with Protective Layer for Battery Safety
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Solution Overview
Problem
Lithium-ion batteries face safety hazards such as fires and explosions due to internal short circuits caused by abnormal conditions like collision or puncture, and existing solutions fail to effectively prevent these incidents while ensuring normal battery operation.
Innovation Solution
A current collector design featuring an insulation layer supporting a conductive layer with a protective layer in between, which increases short-circuit resistance, reduces heat generation, and enhances mechanical strength, thereby improving safety and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alloy having low melting point is added into the material of metal current collector, then the safety of the battery is improved by cutting off current when temperature rises, but the battery cannot continue to operate after safety component responds and the battery still cannot continue to operate
Solution Approach 1:
The current collector is segmented into multiple functional layers: a base metal layer (aluminum or copper) for normal current conduction, and a separate safety component layer comprising thermoplastic resin and electroconductive material. This segmentation allows each layer to perform its specific function independently - the base layer ensures continuous operation while the safety layer provides protective function without affecting the base layer's operational continuity.
Solution Approach 2:
The electroconductive material embedded in the thermoplastic resin acts as an intermediary that bridges the base metal layer and the thermoplastic matrix. This intermediary structure allows the safety component to provide both mechanical support and electrical conduction functions, enabling the battery to maintain operation even after the thermoplastic resin responds to thermal conditions.
2Reliability
If a multilayered current collector with resin layer is adopted, then the safety of the battery is improved by damaging the electrode plate to cut off current when resin melts, but the battery cannot continue to operate after safety component responds
Solution Approach 1:
The current collector is segmented into multiple functional layers: a base metal layer (aluminum or copper) for normal current conduction, and a separate safety component layer comprising thermoplastic resin and electroconductive material. This segmentation allows each layer to perform its specific function independently - the base layer ensures continuous operation while the safety layer provides protective function without affecting the base layer's operational continuity.
Solution Approach 2:
Different regions of the current collector have different properties: the base metal layer provides mechanical strength and continuous conduction, while the safety component layer with thermoplastic resin provides thermal response capability. The local quality of each layer is optimized for its specific function, allowing the overall structure to maintain operation while providing safety protection.
3Power
If the thickness of the conductive layer is increased to ensure sufficient current collection, then the electrical conductivity is improved, but the weight energy density and volume energy density are reduced
Solution Approach 1:
The conductive layer is constructed as a composite material combining metal particles (aluminum, copper, or nickel) dispersed in a thermoplastic resin matrix. This composite structure provides sufficient electrical conductivity through the metal particles while the resin matrix reduces the overall weight compared to solid metal layers, thereby improving weight energy density.
Solution Approach 2:
The thickness of the conductive layer is optimized within a specific range (300nm to 2μm) to balance electrical conductivity and weight. By controlling the thickness parameter and adjusting the metal particle concentration and distribution, the design achieves sufficient current collection capability while minimizing weight, thus improving weight energy density.
4Power
If the thickness of the conductive layer is increased to ensure sufficient current collection, then the electrical conductivity is improved, but the volume energy density is reduced
Solution Approach 1:
The conductive layer is constructed as a composite material combining metal particles (aluminum, copper, or nickel) dispersed in a thermoplastic resin matrix. This composite structure provides sufficient electrical conductivity through the metal particles while the resin matrix reduces the overall volume compared to solid metal layers, thereby improving volume energy density.
Solution Approach 2:
The thickness of the conductive layer is optimized within a specific range (300nm to 2μm) to balance electrical conductivity and volume. By controlling the thickness parameter and adjusting the metal particle concentration and distribution, the design achieves sufficient current collection capability while minimizing volume, thus improving volume energy density.
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 design effectively reduces short-circuit current and heat, preventing thermal runaway and ensuring the battery's safety and operational stability even under abnormal conditions.
Implementation Method 1
When the temperature of the battery reaches a melting point of the material of the resin layer, the resin layer of the current collector melts to damage the electrode plate, thereby cutting off the current
Implementation Method 2
a copper substrate comprising a copper oxide layer that an average content of an oxygen element present within a thickness of 1.0 μm or less from a surface of the copper substrate, is 10.5 at % or more
Data Source
Figure 1~3
Figure 4~6
Figure 7~8
AI summary
The present disclosure provides a current collector, an electrode plate and a battery. The current collector includes an insulation layer and at least one conductive layer located on at least one surface of the insulation layer. The insulation layer is used to support the conductive layer, and the conductive layer is used to support an electrode active material layer. The conductive layer has a thickness of D2, and 300nm≤D2≤2µm. The current collector further includes a protective layer provided on a surface of the conductive layer facing towards the insulation layer. The current collector according to the present disclosure can increase a short-circuit resistance in case of short circuit caused by the battery being abnormal, thereby resulting in protective effect on the conductive layer, and can also increase the bonding force between the insulation layer and the conductive layer, thereby increasing mechanical strength of the current collector.