Multilayer Current Collector Structure for Low-Resistance Battery Films
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Solution Overview
Problem
Current collectors in secondary batteries face issues with porosity and mechanical attenuation due to repeated vacuum evaporation, leading to increased sheet resistance and reduced mechanical properties, which affect battery performance.
Innovation Solution
A multilayer current collector design with alternating carbon coating and metal depositing layers, where the outermost and innermost layers are carbon coating layers, reduces the number of evaporation cycles, thereby minimizing porosity and sheet resistance, and enhances mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If repeated vacuum evaporation is performed to achieve the desired number of metal depositing layers, then the thickness requirement is met, but the porosity of the metal depositing layer increases to up to 30%, reducing current-passing area and increasing sheet resistance
Solution Approach 1:
The patent uses a composite structure consisting of metal depositing layers and carbon coating layers. The carbon coating layers are deposited between and on the metal layers to fill pores and provide conductive pathways, creating a composite material that maintains electrical conductivity even when metal layers have high porosity from repeated evaporation processes
Solution Approach 2:
The carbon coating layers act as intermediary layers between the metal depositing layers. These carbon layers serve multiple functions: they fill the pores in metal layers, provide alternative conductive pathways for electrons, and protect the polymer film from degradation during repeated evaporation cycles
2Manufacturing precision
If the polymer film layer is continuously subjected to vapor deposition 15-20 times to reach the required thickness, then the desired number of layers is achieved, but the mechanical properties of the polymer film layer rapidly attenuate, leading to large attenuation of tensile strength and elongation
Solution Approach 1:
The patent segments the continuous vapor deposition process into alternating cycles: metal layer deposition followed by carbon coating deposition. This segmentation allows the polymer film to be exposed to fewer total evaporation cycles (each metal-carbon pair counts as one cycle rather than multiple metal-only cycles), reducing thermal and mechanical stress on the polymer while still achieving the required total thickness
Solution Approach 2:
The patent changes the material parameter being deposited by alternating between metal and carbon coatings. This parameter change allows the use of a more polymer-friendly deposition process for the carbon layers, which can be deposited at lower temperatures and with less impact on the polymer film's mechanical properties
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 improves electrical conductivity, mechanical strength, and corrosion resistance, ensuring better battery performance by reducing the number of evaporation cycles and protecting the polymer film layer.
Implementation Method 1
The preparation of current collector is completed through the vacuum evaporation process
Implementation Method 2
the carbon coating layer is arranged on two opposite surfaces of the polymer film layer and on the surface of the metal depositing layer by sputtering
Data Source
AI summary
The present invention relates to a current collector having multiple layers of structures and a preparation method therefor. The current collector having the multiple layers of structures comprises a polymer film layer, wherein two surfaces of the polymer film layer that face away from each other are respectively provided with stacked layers, and each stacked layer comprises carbon coatings and metal coatings, which are alternately laminated.