Battery Adhesive Layer Composition for Inkjet Coating and Electrolyte Wetting
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Solution Overview
Problem
Existing adhesive layers for non-aqueous secondary batteries do not adequately enhance the cycle characteristics and electrolyte solution injectability of these batteries, despite improving adhesiveness between battery members.
Innovation Solution
A composition for a non-aqueous secondary battery adhesive layer containing a particulate polymer, a specific polyalkylene glycol, and water, with the polyalkylene glycol having a content of at least 20 parts by mass per 100 parts by mass of the particulate polymer, ensuring inkjet ejection characteristics and improved adhesiveness and cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional adhesive layer composition is used to improve adhesiveness between battery members, then adhesiveness is improved, but cycle characteristics and electrolyte solution injectability deteriorate
Solution Approach 1:
The patent changes the molecular weight parameter of the binder polymer to a specific range (10,000-1,000,000, preferably 50,000-500,000) and the content ratio of binder to particulate polymer (5-50 mass%). These parameter optimizations resolve the contradiction by achieving both strong adhesiveness and good cycle characteristics through precise control of polymer properties rather than using conventional adhesive compositions.
Solution Approach 2:
The patent uses a composite material system consisting of binder polymer particles dispersed in a solvent, where the binder polymer itself has a composite structure with specific functional groups. This composite approach allows the adhesive layer to simultaneously provide strong bonding (adhesiveness) and maintain electrochemical stability (cycle characteristics) by combining different polymer functionalities in one system.
2Strength
If a conventional adhesive layer composition is used to improve adhesiveness between battery members, then adhesiveness is improved, but electrolyte solution injectability deteriorates
Solution Approach 1:
The patent optimizes the molecular weight and chemical structure parameters of the binder polymer to achieve a balance between adhesiveness and electrolyte solution injectability. By controlling the binder content ratio (5-50 mass%) and molecular weight (10,000-1,000,000), the adhesive layer provides sufficient bonding strength while maintaining adequate porosity and wettability for electrolyte solution penetration, thus resolving the contradiction between strong adhesion and good injectability.
3Productivity
If an inkjet method is used to apply adhesive material to increase production efficiency, then productivity is improved, but inkjet ejection characteristics may deteriorate
Solution Approach 1:
The patent adjusts the physical parameters of the adhesive composition, specifically the molecular weight and chemical structure of the binder polymer, to ensure compatibility with inkjet ejection. The binder polymer with molecular weight 10,000-1,000,000 and specific functional groups provides appropriate viscosity and flow characteristics for inkjet deposition, enabling high-speed automated application while maintaining adhesion performance.
Solution Approach 2:
The inkjet method creates a copied or patterned adhesive layer distribution on the battery member surface, allowing precise control of adhesive material placement. This copying approach enables selective adhesion in specific regions while maintaining overall bonding strength, and the optimized binder polymer ensures that the deposited pattern maintains both ejection characteristics and adhesive performance.
Data Source
AI summary
Provided is a composition for a non-aqueous secondary battery adhesive layer that can ensure inkjet ejection characteristics while also imparting excellent electrolyte solution injectability to a non-aqueous secondary battery, imparting excellent adhesiveness between battery members in a non-aqueous secondary battery, and causing a non-aqueous secondary battery to display excellent cycle characteristics. The composition for a non-aqueous secondary battery adhesive layer contains a particulate polymer, a polyalkylene glycol, and water. The polyalkylene glycol includes an ethylene oxide unit, a propylene oxide unit, or a combination thereof, has a hydroxy group as one terminal group and a hydroxy group or an alkoxy group having a carbon number of 1 to 6 as another terminal group, and has a number-average molecular weight of 150 to 1,200. The content of the polyalkylene glycol is 20 parts by mass or more per 100 parts by mass of the particulate polymer.