Composite Current Collector Structure for Better Battery Welding
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Solution Overview
Problem
Conventional lithium ion battery current collectors face issues with difficult welding and poor welding, which affect the practical application and safety of the battery, and result in increased ohmic impedance and internal resistance.
Innovation Solution
A current collector design with alternating first and second metal layers, separated by polymer layers bonded with adhesive layers, where welding occurs only on the metal surfaces without polymer, reducing interference and enhancing welding strength and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper foil is used as current collector, then electrical conductivity is improved, but corrosion resistance deteriorates due to oxidation in electrolyte
Solution Approach 1:
The patent uses aluminum foil as the base material and deposits a copper layer on one surface to create a composite current collector. This composite structure combines the corrosion resistance of aluminum with the high electrical conductivity of copper, resolving the contradiction between conductivity and corrosion resistance. The copper layer provides excellent electrical conductivity while the aluminum substrate prevents corrosion in the electrolyte environment.
2Object-affected harmful factors
If aluminum foil is used as current collector, then corrosion resistance is improved, but electrical conductivity deteriorates
Solution Approach 1:
The patent creates a composite structure by depositing copper on aluminum foil. The aluminum substrate provides corrosion resistance while the copper coating provides high electrical conductivity. This composite material approach allows both properties to coexist, with each material contributing its superior characteristic to the overall current collector performance.
3Reliability
If copper foil is used as current collector, then electrical conductivity is improved, but manufacturing cost increases due to higher material cost
Solution Approach 1:
The patent uses a composite structure with aluminum foil as the base and copper as a coating layer. This approach reduces material cost compared to using pure copper foil, as aluminum is less expensive. The copper layer is applied only where needed for electrical conductivity, optimizing material usage and reducing overall manufacturing cost while maintaining required conductivity performance.
4Reliability
If copper foil is used as current collector, then electrical conductivity is improved, but weight increases
Solution Approach 1:
The patent employs a composite structure where lightweight aluminum foil serves as the substrate and a thin copper layer is deposited on the surface. This combination reduces the overall weight compared to using solid copper foil, as aluminum has lower density. The thin copper coating provides sufficient electrical conductivity while minimizing weight addition, achieving an optimal weight-conductivity balance.
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
Improves welding yield, reduces internal resistance, and enhances the cycle life and safety performance of lithium ion batteries by ensuring effective ion transmission and minimizing temperature rise during charging and discharging.
Implementation Method 1
a copper layer is formed on one surface of the aluminum foil
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3b
AI summary
The present application provides a current collector and a preparation method and application thereof. The current collector includes a first metal layer and a second metal layer provided in a laminated manner, at least one first region and at least one second region are included between the first metal layer and the second metal layer, and the first region and the second region are alternately arranged in a first direction; the first region is provided with a polymer layer, and the polymer layer is respectively bonded to the first metal layer and the second metal layer through an adhesive layer. The current collector of the present application not only has a high welding yield, effectively saving the production cost of the lithium ion battery, but also can reduce the internal resistance of the lithium ion battery, significantly improving the cycle performance and the safety performance of the lithium ion battery.