PP/CA Battery Separator with Water-Formed Pore Channels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing PP-based separators in lithium-ion batteries lack mechanical, thermal, and electrical stability, which can lead to fire risks and performance degradation over time.
Innovation Solution
A double-layer separator is created by bonding a polypropylene (PP) film with a cellulose acetate (CA) film using a plasticizer and water pressure treatment, forming pore channels that enhance mechanical and thermal stability while maintaining electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-layer PP separator is used, then the manufacturing process is simple, but the thermal stability and mechanical strength are insufficient
Solution Approach 1:
The patent applies composite materials by combining PP nonwoven fabric as the base layer with a CA coating layer. This composite structure provides both the mechanical strength from the PP substrate and the thermal stability from the CA layer, resolving the contradiction between strength requirements and structural simplicity.
Solution Approach 2:
The separator is segmented into two functional layers: a PP nonwoven fabric layer for mechanical support and a CA coating layer for thermal stability. This segmentation allows each layer to specialize in its optimal function, achieving high strength without excessive overall complexity.
2Temperature
If a single-layer PP separator is used, then the manufacturing process is simple, but the thermal stability is insufficient
Solution Approach 1:
The CA coating layer is applied on top of the PP nonwoven fabric to provide enhanced thermal stability. The CA material maintains its structural integrity at higher temperatures, preventing separator failure and ensuring battery safety without requiring a completely complex multi-layer structure.
Solution Approach 2:
The thermal stability enhancement is applied locally through the CA coating layer rather than requiring the entire separator structure to be complex. The coating provides thermal protection exactly where needed at the separator surface, maintaining overall structural simplicity.
3Object-affected harmful factors
If the separator structure is simplified, then the manufacturing is easy, but the fire protection capability is reduced
Solution Approach 1:
The combination of PP nonwoven fabric and CA coating creates a composite separator that provides superior fire protection. The CA layer acts as a thermal barrier that prevents fire propagation, reducing fire risk without requiring an overly complex separator design.
Solution Approach 2:
The separator design converts the potential harm of high-temperature operation into benefit by using the CA coating's thermal stability to prevent fire. The structure transforms thermal stress into a protective mechanism that actively prevents fire rather than merely resisting it.
4Reliability
If a double-layer PP/CA separator is manufactured with pore channels, then the ionic conductivity is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The PP nonwoven fabric substrate is prepared in advance with its inherent porous structure before the CA coating is applied. This preliminary preparation of the base layer's pore structure ensures that ionic conductivity pathways are established before the thermal stability layer is added, simplifying the overall manufacturing sequence.
Solution Approach 2:
The PP nonwoven fabric provides a pre-formed porous matrix that facilitates ion transport. The CA coating is applied to this porous structure in a way that maintains the pore channels, allowing ionic conductivity to be improved without requiring complex post-processing steps to create pores.
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 resulting separator exhibits improved thermal stability, reduced fire risk, and sustained electrical properties over long-term use, enhancing the durability and performance of batteries, particularly in microbial fuel cells.
Implementation Method 1
bonding a polypropylene (PP) film with a cellulose acetate (CA) film using a plasticizer
Implementation Method 2
forming a pore channel penetrating the PP and CA films layer by applying water pressure to the PP/CA separator through water pressure treatment
Data Source
AI summary
Proposed is a double-layer separator composed of polypropylene (PP) and cellulose acetate (CA), wherein a PP film is coated with a CA mixed solution containing a plasticizer, thus forming pores in a CA film through water pressure treatment. When the separator is applied as a separator for a battery, the thermal stability and mechanical stability of the separator enable a battery having thermal stability and long-term usability to be implemented.