Dual-Separator Electrode Assembly for Battery Cycling Stability
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Solution Overview
Problem
Existing secondary batteries face challenges in maintaining good electrochemical performance, particularly in cycling processes due to issues such as damage to active materials and electrolyte extrusion during expansion, leading to reduced battery performance.
Innovation Solution
An electrode assembly design featuring different separators, where one separator includes a porous coating and the other does not, with the porous coating thickness ranging from 0.5 μm to 8 μm, providing expansion space and improved bonding, thereby reducing damage and enhancing ion transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a separator without porous coating is used, then manufacturing simplicity is maintained, but cycling performance deteriorates due to compression-induced damage and electrolyte extrusion
Solution Approach 1:
The patent applies local quality by using one separator without porous coating (maintaining manufacturing simplicity) and another separator with porous coating (improving cycling performance). The porous coating is applied locally to specific separators based on their position and functional requirements, allowing different regions of the battery to have different separator properties optimized for their specific roles.
Solution Approach 2:
The patent uses composite materials by combining a base separator material with a porous coating layer. The porous coating acts as a composite structure that provides expansion space and protects against compression damage, while the base material maintains the separator's fundamental separation function. This composite approach resolves the contradiction between manufacturing simplicity and cycling performance.
2Reliability
If expansion space is reserved in the cell, then active material damage is reduced, but device volume increases
Solution Approach 1:
The patent uses thin film separators with porous coatings that provide expansion accommodation without requiring large volume increases. The flexible nature of the separator structure allows it to expand and contract with the active materials during cycling, protecting against damage while minimizing the overall volume penalty.
Solution Approach 2:
The patent changes the physical parameters of the separator by introducing porous coatings with specific thickness ranges (0.5 μm to 8 μm) and porosity characteristics. These parameter changes allow the separator to provide expansion space more efficiently, accommodating volume changes during cycling without proportionally increasing the overall cell volume.
3Strength
If porous coating thickness is increased, then bonding function and heat-resistance improve, but manufacturing complexity and cost increase
Solution Approach 1:
The patent optimizes the porous coating thickness within a specific range (0.5 μm to 8 μm) to achieve the desired bonding strength and heat-resistance without excessive complexity. By controlling the thickness parameter within this optimized range, the patent balances performance improvement with manufacturing feasibility, avoiding the need for overly complex multi-layer structures.
Solution Approach 2:
The patent applies porous coatings selectively based on position and functional requirements rather than uniformly across all separators. This local application strategy reduces overall manufacturing complexity while still providing enhanced bonding and heat-resistance where most needed, particularly on separators that experience higher stress or temperature exposure.
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 alleviates compression-induced damage and electrolyte extrusion, ensuring effective wetting and ion transmission, thus improving cycling performance and safety of the battery.
Implementation Method 1
the other of the first separator and the second separator comprises a porous coating, and the thickness of the porous coating is 0.5 μm to 8 μm
Implementation Method 2
the cell is effectively wetted in the electrolyte solution in the expansion process, which helps transmit ions
Data Source
AI summary
An electrode assembly, a battery, and an electric device. The electrode assembly includes a first electrode, a second electrode, a first separator, and a second separator. One of the first separator and the second separator is disposed between the first electrode and the second electrode. The other of the first separator and the second separator is disposed on a side that is of the first electrode or the second electrode and that faces away from the first separator. One of the first separator and the second separator does not include a porous coating. The other of the first separator and the second separator includes a porous coating. The thickness of the porous coating is 0.5 μm to 8 μm. The electrode assembly in the present application includes a specific first separator and a specific second separator, which can effectively improve cycling performance of the battery.