Positive Current Collector with High-Density Metal Layer
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Solution Overview
Problem
Existing secondary battery current collectors, particularly those made of plastic with a metal layer, face performance degradations in processing and electrical performance, which hinder the achievement of high weight energy density and stability.
Innovation Solution
A positive current collector with a support layer and a metal conductive layer, where the metal conductive layer has a density ratio greater than or equal to 0.89, made from materials like aluminum, nickel, or silver alloys, is used to maintain structural stability and electrical conductivity, even under stretching, thereby enhancing the electrochemical device's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a plastic current collector plated with a metal layer is used to reduce weight, then the weight energy density is improved, but the processing performance and electrical performance deteriorate
Solution Approach 1:
The patent uses a composite structure consisting of a plastic support layer and a metal conductive layer. The support layer provides mechanical strength and processing performance, while the metal layer provides electrical conductivity. This composite material approach resolves the contradiction by combining materials with complementary properties to achieve both weight reduction and maintained performance.
Solution Approach 2:
The metal conductive layer is applied locally on the surface of the plastic support layer rather than using solid metal throughout. This localized application of metal material provides the necessary electrical conductivity only where needed, significantly reducing overall weight while maintaining processing performance of the plastic substrate.
2Weight of moving object
If the metal conductive layer is made thinner to reduce weight, then the weight energy density is improved, but the structural stability and electrical conductivity under stretching deteriorate
Solution Approach 1:
The composite structure of plastic support layer and metal conductive layer provides both weight reduction and structural stability. The plastic support layer has appropriate mechanical properties that prevent excessive deformation during stretching, while the thin metal layer maintains electrical conductivity. This composite approach allows thinner metal layers without sacrificing structural stability.
Solution Approach 2:
The patent optimizes the thickness parameter of the metal conductive layer and controls its density ratio to achieve the right balance between weight reduction and maintaining electrical performance under stretching conditions.
3Weight of moving object
If the metal conductive layer is made thinner to reduce weight, then the weight energy density is improved, but the resistance increases sharply due to stretching deformation
Solution Approach 1:
The plastic support layer with appropriate mechanical properties prevents excessive stretching deformation, thereby protecting the thin metal conductive layer from developing high resistance. The composite structure allows the metal layer to be thinner while the plastic substrate provides the mechanical integrity needed to maintain electrical conductivity during battery operation and cycling.
Data Source
AI summary
Positive current collector, positive plate, electrochemical device and apparatus are disclosed. The positive current collector includes a support layer and a metal conductive layer disposed on the support layer, where a ratio of a density of the metal conductive layer to an intrinsic density of a material of the metal conductive layer is greater than or equal to 0.89, and the material of the metal conductive layer is selected from one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. The positive current collector can provide simultaneously both low weight and high electrical performance, thus enabling the electrochemical device to achieve both high weight energy density and electrochemical performance at the same time.