Composite Current Collector Primer for Battery Electrode Machinability
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Solution Overview
Problem
Lithium-ion batteries face challenges in achieving high mass energy density and volume energy density due to limitations in current collector materials, leading to performance degradations in machinability, safety, and electrical performance, particularly with composite current collectors that have poor conductivity and are vulnerable to damage.
Innovation Solution
The introduction of a composite current collector with a conductive primer layer, comprising a support layer, a thin conductive layer, and a water-based bonding agent, which enhances the interface between the current collector and the electrode active material layer, improving bonding force and conductivity, and reducing direct current resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a plastic current collector plated with a metal layer is used to increase energy density, then mass energy density and volume energy density are improved, but machinability and safety performance deteriorate
Solution Approach 1:
The current collector is segmented into multiple functional layers: a plastic support layer (providing mechanical strength and machinability), a metal conductive layer (providing electrical conductivity), and an oxide protection layer (providing safety and stability). Each layer performs its specific function, resolving the contradiction between energy density and machinability.
Solution Approach 2:
A composite current collector structure is employed combining plastic and metal materials. The plastic support layer provides good machinability and structural integrity, while the plated metal layer provides electrical conductivity. This composite structure achieves both high energy density and good machinability simultaneously.
2Quantity of substance
If a punched current collector or plastic current collector plated with a metal layer is used to reduce weight, then mass energy density is improved, but electrical performance and safety performance deteriorate
Solution Approach 1:
The composite structure combines lightweight plastic material with a thin metal conductive layer. The plastic support layer reduces overall weight while the metal layer maintains electrical performance. The oxide layer on the metal surface further enhances electrical stability and safety, resolving the contradiction between mass energy density and electrical performance.
Solution Approach 2:
The metal conductive layer is applied locally on the plastic current collector surface where electrical conductivity is needed, rather than using entirely metal. This localized application reduces overall weight for improved mass energy density while maintaining electrical performance through the conductive metal layer.
3Quantity of substance
If the conductive layer thickness is reduced to minimize volume, then volume energy density is improved, but conductivity and vulnerability to damage increase
Solution Approach 1:
The composite structure uses a plastic support layer with a thin metal conductive layer plated on it. The plastic layer provides mechanical strength and volume, while the thin metal layer (optimized thickness) provides necessary conductivity. This combination achieves high volume energy density while maintaining adequate electrical conductivity through the metal layer.
Solution Approach 2:
The thickness of the metal conductive layer is optimized to a specific range to balance conductivity and volume energy density. By controlling the metal layer thickness parameter, the patent achieves sufficient electrical conductivity while minimizing volume occupied by the conductive layer, thereby improving volume energy density.
4Device complexity
If a conventional current collector structure is used to simplify design, then device complexity is reduced, but bonding force and electrical performance deteriorate
Solution Approach 1:
The patent employs a composite current collector with plastic support layer and metal conductive layer. This composite structure inherently provides stronger bonding force between layers due to the metallurgical bond between plastic and metal, while the layered structure remains relatively simple in design and manufacturing process.
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 configuration enhances the electrical and safety performance of lithium-ion batteries by improving the bonding force between the current collector and the electrode active material layer, reducing resistance, and preventing phenomena like great polarization and lithium precipitation, thereby ensuring long-term reliability.
Implementation Method 1
a conductive primer layer including a conductive material and a bonding agent is further disposed between the current collector and the electrode active material layer, and the bonding agent in the conductive primer layer includes a water-based bonding agent
Implementation Method 2
the current collector includes a support layer and a conductive layer disposed on at least one surface of the support layer... a conductive primer layer including a conductive material... improving bonding force and conductivity, and reducing direct current resistance
Data Source
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AI summary
This application relates to the battery field, and specifically, to an electrode plate, an electrochemical apparatus, a battery module, a battery pack, and a device. The electrode plate in this application includes a current collector and an electrode active material layer disposed on at least one surface of the current collector, where the current collector includes a support layer and a conductive layer disposed on at least one surface of the support layer, a single-side thickness D2 of the conductive layer satisfies 30 nm ≤ D2 ≤ 3 µm, a conductive primer layer including a conductive material and a bonding agent is further disposed between the current collector and the electrode active material layer, and the bonding agent in the conductive primer layer includes a water-based bonding agent. The electrode plate in this application has good machinability. An electrochemical apparatus including the electrode plate has high energy density, good electrical performance, and long-term reliability.