Battery Functional Layer Composition for Thin Coating Without Cissing
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Solution Overview
Problem
Conventional non-aqueous secondary battery functional layers face challenges in achieving uniform thickness and preventing excessive metal deposition on electrodes during charging, leading to potential short-circuiting and safety issues.
Innovation Solution
A composition comprising organic particles, a binder, and a wetting agent in an aqueous medium, where the wetting agent content is between 1 to 5 parts by mass per 100 parts of organic particles, inhibits cissing and excessive metal deposition by using a surfactant with an HLB value of 9 or higher, such as sulfosuccinic acid esters or non-ionic surfactants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the functional layer is applied as a thinner film to reduce thickness, then the functional layer thickness is reduced, but cissing occurs and uniform thickness cannot be achieved
Solution Approach 1:
The patent changes the chemical composition parameters of the slurry by incorporating a wetting agent with specific HLB value (8-16) and controlling its content (0.1-5 parts by mass per 100 parts of organic particles). This parameter change modifies the surface tension and wetting properties of the slurry, enabling uniform thin film formation without cissing while maintaining the desired functional layer thickness
Solution Approach 2:
The wetting agent acts as an intermediary substance between the slurry components and the substrate. It mediates the interaction by reducing surface tension and improving wetting characteristics, allowing the slurry to spread uniformly as a thin film without forming cissing defects, thus enabling both thickness reduction and uniformity
2Length of moving object
If conventional composition is used to form thin functional layer, then thickness reduction is achieved, but cissing occurs during application
Solution Approach 1:
The patent modifies the slurry composition parameters by adding a wetting agent with specific HLB value range (8-16) and controlling its concentration (0.1-5 parts by mass per 100 parts of organic particles). This parameter change alters the surface tension and flow characteristics of the slurry, preventing cissing during application while enabling thin film formation
Solution Approach 2:
The wetting agent serves as an intermediary that modifies the interfacial properties between the slurry and substrate. It reduces surface tension and improves wetting behavior, thereby eliminating cissing defects during the coating process and enabling successful thin film formation
3Quantity of substance
If functional layer is made thinner to increase energy density, then energy density increases, but uniform thickness cannot be achieved due to cissing
Solution Approach 1:
The patent changes the chemical parameters of the slurry composition by incorporating a wetting agent with specific HLB value (8-16) and controlling its content (0.1-5 parts by mass per 100 parts of organic particles). This enables the formation of uniform thin functional layers that increase battery energy density while maintaining manufacturing precision and avoiding cissing defects
4Manufacturing precision
If wetting agent content is increased to prevent cissing, then cissing is inhibited, but excessive metal deposition occurs on electrode during charging
Solution Approach 1:
The patent optimizes the wetting agent content parameter within a specific range (0.1-5 parts by mass per 100 parts of organic particles) and specifies an HLB value range (8-16). This precise parameter control achieves the minimum effective concentration needed to prevent cissing and ensure uniform thickness, while avoiding excessive wetting that would cause metal deposition during battery charging
Solution Approach 2:
The patent applies the principle of partial action by using a controlled, moderate amount of wetting agent rather than excessive quantities. The specified range (0.1-5 parts by mass) provides just enough wetting effect to prevent cissing and ensure uniform film formation, while avoiding the harmful effects of excessive wetting agent that would lead to metal deposition during charging
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 enables the formation of functional layers with uniform thickness and prevents excessive metal deposition on electrodes, enhancing the safety and performance of non-aqueous secondary batteries by reducing cissing and foaming, while maintaining adhesiveness.
Implementation Method 1
a wetting agent, and water, wherein content of the wetting agent is more than 1 part by mass and not more than 5 parts by mass per 100 parts by mass of the organic particles
Implementation Method 2
by compounding a specific amount of a wetting agent in preparation of a composition for a functional layer obtained by dispersing and/or dissolving organic particles and a binder in an aqueous medium, it is possible to inhibit cissing when the composition for a functional layer is applied as a thin film
Implementation Method 3
ensure various characteristics of a secondary battery without excessively increasing the amount of metal deposited on an electrode during charging of the secondary battery
Data Source
AI summary
Provided is a composition for a non-aqueous secondary battery functional layer that inhibits cissing in thin film application and enables formation of a functional layer that does not excessively increase the amount of metal deposited on an electrode during secondary battery charging. The composition for a functional layer contains organic particles, a binder, a wetting agent, and water. Content of the wetting agent is more than 1 part by mass and not more than 5 parts by mass per 100 parts by mass of the organic particles.