Segmented Current Collector with Holes for Battery Safety
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Solution Overview
Problem
Lithium-ion batteries face safety hazards due to internal short circuits caused by abnormal conditions like collision or puncture, which existing solutions fail to effectively prevent, leading to potential fires or explosions and inability to continue operating.
Innovation Solution
A current collector design featuring a thin conductive layer on an insulation layer with holes, increasing short-circuit resistance, reducing metal burrs, and improving electrolyte wettability, thereby enhancing safety and electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alloy having low melting point is added into the material of metal current collector to improve safety by melting and breaking the circuit, then the battery safety is improved, but the battery cannot continue to operate and the short-circuit current and heat generated are still large
Solution Approach 1:
The current collector is segmented into multiple functional layers: an insulation layer and a conductive layer. The conductive layer is further divided into a first conductive layer on the positive electrode side and a second conductive layer on the negative electrode side. This segmentation allows each layer to perform its specific function - the insulation layer provides electrical isolation while the conductive layers provide current collection, resolving the contradiction between safety and continuous operation capability
Solution Approach 2:
The current collector uses a composite structure combining insulation material and conductive material in specific layers. The insulation layer is made of materials like polyolefin or aramid, while the conductive layers are made of metals like aluminum or copper. This composite material approach allows the current collector to simultaneously provide electrical insulation (safety) and electrical conduction (continuous operation), resolving the technical contradiction
2Reliability
If a multilayered current collector with resin layer is adopted to improve safety by melting and damaging the electrode plate, then the battery safety is improved, but the battery cannot continue to operate and metal burrs are generated
Solution Approach 1:
The conductive layer is designed with localized properties - it has high electrical conductivity where needed for current collection but is positioned and dimensioned to minimize harmful effects. The thickness is controlled at 3-20 μm to provide sufficient conductivity while reducing metal burr generation. The conductive layer is applied selectively on the insulation layer rather than throughout the entire current collector structure
Solution Approach 2:
The current collector incorporates a porous structure with pore volume ratio of 10-40% and average pore size of 1-50 μm. This porous structure reduces the density of the current collector, minimizing metal burr generation while maintaining electrical conductivity through the porous conductive layer. The porous structure also allows electrolyte penetration, maintaining battery operation capability
3Power
If the conductive layer thickness is increased to improve electrical conductivity, then the electrical performance is improved, but the short-circuit resistance is reduced and safety is compromised
Solution Approach 1:
The insulation layer acts as an intermediary between the positive and negative electrodes, providing electrical isolation and preventing direct short circuits. The conductive layers are applied on the insulation layer, allowing current collection without compromising the insulation barrier. This intermediary structure enables both high electrical conductivity (through the conductive layers) and high short-circuit resistance (through the insulation layer)
Solution Approach 2:
The composite structure of insulation layer plus conductive layers creates a material system that combines the properties of both materials. The insulation layer provides high electrical resistance and thermal stability, while the conductive layers provide high electrical conductivity for current collection. The synergistic combination resolves the contradiction between electrical conductivity and short-circuit resistance
4Strength
If a thick metal current collector is used to ensure structural strength, then the mechanical strength is improved, but the weight increases and electrochemical performance is reduced
Solution Approach 1:
The current collector uses a porous structure with controlled pore volume ratio (10-40%) and average pore size (1-50 μm). This porous structure significantly reduces the weight and density of the current collector compared to solid metal structures, while maintaining sufficient mechanical strength through the porous network. The porous structure also enhances electrochemical performance by allowing electrolyte penetration and increasing surface area for reactions
Solution Approach 2:
The composite structure combining insulation material and conductive material in specific layers provides both mechanical strength and electrical functionality. The insulation layer provides structural support and mechanical strength, while the conductive layers provide electrical conductivity. This composite approach allows weight reduction compared to traditional solid metal current collectors while maintaining both strength and electrochemical performance
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, improves safety by minimizing metal burrs, and enhances electrochemical properties such as high-rate charge-discharge capabilities and cycle life while maintaining battery operation.
Implementation Method 1
a conductive layer at least located on at least one surface of the insulation layer. The conductive layer has a thickness of D2, wherein 30 nm≤D2≤3 μm
Implementation Method 2
an insulation layer; and a conductive layer at least located on at least one surface of the insulation layer
Implementation Method 3
The current collector is provided with a plurality of holes penetrating through the insulation layer and the conductive layer
Implementation Method 4
enhances electrolyte wettability
Implementation Method 5
the conductive layer of the current collector of the present disclosure is thin, the metal burrs occurring inside the battery cell under abnormal conditions such as nailing may be small
Implementation Method 6
a short-circuit resistance can be increased in the event of the short circuit under abnormal conditions of the battery, so that the short-circuit current and the short-circuit heats generated during the short circuit are greatly reduced
Data Source
AI summary
The present disclosure relates to the technical field of battery, and in particular, relates to a current collector, an electrode plate including the current collector, and an electrochemical device. The current collector includes an insulation layer; and a conductive layer at least located on at least one surface of the insulation layer. The conductive layer has a thickness of D2, where 30 nm≤D2≤3 μm. The current collector is provided with a plurality of holes penetrating through the insulation layer and the conductive layer.