Battery Separator Coating With Open-Celled Pores for Uniform Ion Transport
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Solution Overview
Problem
Existing methods for depositing separator material in battery technologies face challenges in achieving uniform thickness, efficient ion transport, and preventing electrical shorts due to dendrite growth.
Innovation Solution
A method involving spray-coating a polymer-polymer-solvent liquid mixture over a substrate, followed by solvent evaporation, polymer dissolution, and electron beam irradiation to form a separator film with an open-celled network of pores, ensuring uniform thickness and ion transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods are used to deposit separator material, then the deposition process can be completed, but uniform thickness control is difficult to achieve
Solution Approach 1:
The patent controls the deposition process by precisely adjusting parameters including substrate temperature (maintained below the solvent's dew point to prevent premature condensation), solvent composition ratios, polymer concentration, and deposition rate. These parameter changes enable uniform film thickness while maintaining process feasibility
Solution Approach 2:
The system incorporates real-time monitoring and feedback control of substrate temperature and deposition conditions. By continuously measuring and adjusting process parameters based on actual conditions, the system achieves consistent film thickness uniformity across the substrate surface
2Reliability
If a dense separator structure is formed to prevent electrical shorts, then safety is improved, but ion transport efficiency decreases
Solution Approach 1:
The patent creates a porous separator film structure through controlled phase separation during deposition. The porous structure provides interconnected channels that allow efficient ion transport while the overall film density and pore distribution prevent dendrite penetration and electrical shorts
Solution Approach 2:
The separator film is formed as a composite structure combining polymer matrix with controlled pore phases. This composite architecture simultaneously achieves mechanical integrity for short prevention and open pathways for ion conduction, resolving the contradiction between safety and efficiency
3Productivity
If rapid solvent evaporation is used to form the separator film, then production speed is improved, but film uniformity and pore structure control deteriorate
Solution Approach 1:
The substrate is pre-cooled below the solvent's dew point before deposition begins. This preliminary temperature control prevents premature solvent condensation and evaporation during the deposition process, allowing uniform film formation at controlled rates while maintaining productivity
Solution Approach 2:
The deposition process uses controlled periodic solvent evaporation and phase separation cycles. By regulating the timing and rate of solvent removal through temperature control and atmospheric conditions, the system achieves uniform pore structure formation without sacrificing production speed
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 method achieves a uniform separator film with controlled thickness and open-celled pores, enhancing ion transport and preventing electrical shorts in battery cells.
Implementation Method 1
heating the first substrate and the constellation of separator material droplets to the target substrate temperature to evaporate the first solvent out of the constellation of separator material droplets
Implementation Method 2
washing the constellation of separator material droplets with a second solvent to dissolve the second polymer out of the constellation of separator material droplets and render an open-celled network of pores
Implementation Method 3
irradiating the constellation of separator material droplets and the first substrate to crosslink the first polymer and form a separator film on the first substrate
Data Source
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AI summary
One variation of the method includes: receiving a section of a substrate tape including a substrate within a coating zone; depositing a constellation of separator material droplets over the first substrate, each droplet in the constellation of separator material droplets including a first solvent, a first polymer, and a second polymer; heating the substrate and the proportion of the separator material to a first temperature; dissolving the second polymer out of the constellation of separator material droplets to render an open-celled network of pores by washing the constellation of separator material droplets and the substrate with a second solvent; and irradiating the constellation of separator material droplets to crosslink the first polymer and form a discrete separator layer with the open- celled network of pores sized to transport ions through the discrete separator layer.