Composite Current Collector Structure for Heat Transfer and Flame Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional composite current collectors in lithium batteries suffer from poor thermal conductivity and flame retardancy, leading to safety risks such as combustion and explosion, and are limited by high mass specific gravity and high costs due to the use of metal foils like aluminum and copper.
Innovation Solution
A multilayered composite current collector structure with varying metal particle sizes and compositions, including a first metal layer close to the base film layer for high compactness and thermal conductivity, a second metal layer for improved bonding, and a third metal layer with larger particles for enhanced electrical conductivity and surface roughness, combined with a flexible organic polymer base film layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional composite current collector uses organic polymer base film layer, then ductility is improved, but thermal conductivity and flame retardancy deteriorate
Solution Approach 1:
The patent applies composite materials by combining organic polymer base film with multiple metal particle layers to achieve both ductility from the polymer and thermal conductivity from the metal particles, resolving the contradiction between improved ductility and deteriorated thermal conductivity
Solution Approach 2:
The patent uses local quality by creating different metal particle layers with varying particle sizes at different locations: smaller particles in the first layer for thermal conductivity near the base film, and larger particles in the third layer for electrical conductivity at the surface, thus addressing thermal conductivity issues locally where needed
2Stability of the object's composition
If conventional composite current collector uses organic polymer base film layer, then ductility is improved, but flame retardancy deteriorates
Solution Approach 1:
The patent combines organic polymer with metal particle layers to create a composite structure that maintains the ductility of the polymer while adding flame retardancy through the metal particles, which have high melting points and do not combust
Solution Approach 2:
The patent converts the harmful combustibility of the organic polymer into a benefit by layering metal particles that act as thermal barriers and flame retardants, transforming the weakness of the polymer into an opportunity for enhanced safety through the protective metal layers
3Temperature
If metal foil current collector is used, then thermal conductivity is improved, but mass specific gravity increases
Solution Approach 1:
The patent applies local quality by using metal particles only in specific layers where thermal and electrical conductivity are needed, rather than using solid metal foil throughout, thus reducing overall mass while maintaining necessary thermal conductivity in critical areas
Solution Approach 2:
The patent changes the physical state and parameters of metal from continuous foil to discrete particles with varying sizes, allowing optimization of thermal conductivity while significantly reducing mass specific gravity compared to solid metal foils
4Reliability
If copper foil is used as current collector, then electrical conductivity is improved, but cost increases
Solution Approach 1:
The patent applies local quality by concentrating metal particles primarily in the first layer adjacent to the base film where electrical conductivity is most critical for current collection, while using fewer or no metal particles in outer layers, thus reducing copper content and cost while maintaining necessary electrical conductivity
Solution Approach 2:
The patent uses composite materials combining organic polymer with metal particles, replacing expensive solid copper foil with a more cost-effective composite structure that achieves comparable electrical conductivity through strategic metal particle placement
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 solution enhances thermal conductivity, flame retardancy, and electrical conductivity while reducing mass and improving ductility, thereby increasing the safety and energy density of lithium batteries.
Implementation Method 1
the first metal layer close to the base film layer has a small particle size, so that the first metal layer has high compactness, and can effectively transfer the heat of the base film layer to outside
Implementation Method 2
the metal particles in the third metal layer far from the base film layer has large particle size, which can increase the surface roughness of the composite current collector, and enhance the bonding strength between the composite current collector and the electrode active material
Data Source
AI summary
The present application relates to the technical field of batteries. The present application provides a flame-retardant composite current collector, comprising a base film layer and a metal layer. The base film layer comprises an organic polymeric material. The metal layer is arranged on at least one surface of the base film layer, and the metal layer comprises a first metal layer, a second metal layer, and a third metal layer successively stacked on the base film layer. First metal particles are provided in the first metal layer, second metal particles are provided in the second metal layer, and third metal particles are provided in the third metal layer; and the particle size D1 of the first metal particles, the particle size D2 of the second metal particles, and the particle size D3 of the third metal particles satisfy the following relationships: D1 ≤ D2, and D1<D3. According to the composite current collector, the thermal conductivity and flame resistance of the composite current collector can be improved, thereby improving the safety performance of a battery comprising the composite current collector and the safety performance of an electric device.