Conductive Composite Separator for Uniform Metal Ion Deposition
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Solution Overview
Problem
Metal secondary batteries face safety issues due to nonuniform deposition of metal ions on the negative electrode, leading to the formation of dendrites, which affect the service life and safety of the battery.
Innovation Solution
A composite separator with a conductive coating on a separator substrate, optionally with a ceramic coating, to improve current density and reduce overpotential, thereby facilitating uniform deposition of metal ions and reducing dendrite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal ions are deposited on the negative electrode without a conductive coating, then the battery structure is simple, but the current density is insufficient leading to nonuniform deposition and dendrite formation
Solution Approach 1:
The patent applies composite materials by combining a separator substrate with a conductive coating layer to create a composite separator. This composite structure improves current density and deposition uniformity while managing the increased structural complexity through functional integration.
Solution Approach 2:
The conductive coating acts as an intermediary layer between the separator substrate and the metal ions. This intermediate layer facilitates uniform current distribution and promotes even metal ion deposition, resolving the contradiction between simple structure and uniform deposition.
2Reliability
If the conductive coating is made thicker to improve current density, then deposition uniformity improves, but self-discharge increases
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness of the conductive coating within a specific range (0.05-10 μm). This controlled parameter adjustment achieves sufficient current density improvement while minimizing self-discharge losses, resolving the contradiction between deposition uniformity and energy loss.
3Reliability
If no ceramic coating is added, then the separator structure is simple, but thermal shrinkage is high causing internal short circuits
Solution Approach 1:
The patent applies composite materials by incorporating a ceramic coating layer onto the separator substrate. This composite structure provides thermal stability and prevents shrinkage-induced short circuits, while the layered composite design manages the complexity through functional specialization.
4Device complexity
If the conductive coating is placed directly on the separator substrate, then the structure is simple, but conductive material infiltrates the separator substrate causing self-discharge
Solution Approach 1:
The ceramic coating serves as an intermediary barrier layer between the conductive coating and the separator substrate. This intermediate layer prevents conductive material infiltration into the substrate, eliminating self-discharge while maintaining the relatively simple overall structure.
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 composite separator enhances the safety and cycle performance of metal secondary batteries by ensuring uniform ion deposition and reducing the risk of internal short circuits.
Implementation Method 1
improve the current density for deposition of metal ions on a negative electrode current collector such that the metal ions are evenly deposited
Implementation Method 2
The ceramic coating can effectively reduce the thermal shrinkage rate of the composite separator such that the thermal stability of the composite separator is improved
Data Source
AI summary
A composite separator, a secondary battery, and a power consuming apparatus. The composite separator includes a separator substrate and a conductive coating disposed on a side of the separator substrate. The conductive coating in the composite separator is conducive to improving the current density for deposition of metal ions on a negative electrode current collector such that the metal ions are evenly deposited, and is also conducive to reducing an overpotential of a battery including same such that metal dendrites are further alleviated.