Conductive Adhesive Composition for Lithium-Ion Battery Tab Bonding
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Solution Overview
Problem
Existing conductive adhesives for lithium-ion batteries suffer from low shear strength, high swelling and dissolution rates in electrolyte solutions, poor conductivity, and oxidation issues, which affect battery performance and production efficiency.
Innovation Solution
A conductive adhesive comprising a substrate of modified epoxy resin, polyurethane, and polyimide, combined with conductive fillers such as Au, Ag, Ni, Cu, Zn, graphite, or graphene, to enhance mechanical performance, bonding, and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser welding is used to fasten tab and terminal, then bonding strength is achieved, but welding defects occur affecting production efficiency
Solution Approach 1:
The patent replaces the laser welding process (thermal/mechanical system) with a conductive adhesive bonding process (chemical system). The conductive adhesive forms a bonding layer between the tab and terminal through chemical adhesion, eliminating welding defects while maintaining bonding strength and improving production efficiency through a simpler, defect-free process.
Solution Approach 2:
The conductive adhesive itself is a composite material combining organic polymer matrix (for bonding) with conductive fillers (for electrical conductivity). This composite structure allows the adhesive to simultaneously provide mechanical bonding strength and electrical conductivity, replacing the need for laser welding while maintaining functional requirements.
2Productivity
If conventional conductive adhesive is used to replace laser welding, then production efficiency improves, but shear strength becomes too low
Solution Approach 1:
The patent creates a composite conductive adhesive by combining an organic polymer matrix (providing bonding strength) with conductive filler particles (providing electrical conductivity). This composite structure enables the adhesive to simultaneously achieve high shear strength through the polymer matrix and adequate electrical conductivity through the conductive filler network.
Solution Approach 2:
The patent optimizes parameters including the ratio of conductive filler to polymer matrix, particle size distribution of fillers, and curing conditions to simultaneously maximize both shear strength and electrical conductivity. By carefully controlling these parameters, the adhesive achieves bonding strength sufficient to replace laser welding while maintaining production efficiency benefits.
3Reliability
If conductive adhesive with high conductive filler content is used, then conductivity improves, but swelling and dissolution rates in electrolyte increase
Solution Approach 1:
The patent optimizes the conductive filler content within a specific range and adjusts the polymer matrix composition to provide adequate conductivity while maintaining low swelling and dissolution rates. The polymer matrix acts as a protective medium that prevents excessive electrolyte penetration, thereby stabilizing the conductive filler network and preventing aggregation or detachment during battery operation.
Solution Approach 2:
The composite structure of polymer matrix and conductive filler creates a synergistic effect where the polymer provides structural integrity and chemical stability, preventing the conductive filler from dissolving or aggregating in the electrolyte, while the conductive filler provides the necessary electrical conductivity for battery operation.
4Ease of manufacture
If conventional conductive adhesive is used, then bonding function is provided, but oxidation issues affect performance
Solution Approach 1:
The polymer matrix in the conductive adhesive creates a protective environment that shields the conductive filler particles from oxidation by electrolyte and air. This protective barrier prevents oxidative degradation of the conductive filler, maintaining electrical conductivity and bonding performance throughout the battery's operational life.
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 proposed conductive adhesive achieves high shear strength, improved conductivity, and stability in electrolyte solutions, thereby enhancing the reliability and performance of lithium-ion batteries while reducing production defects.
Implementation Method 1
The conductive filler particles contact each other, and a tunnel effect enables the particles to form the current channels
Implementation Method 2
The active functional group carboxyl can react with an epoxy group in the epoxy resin
Data Source
AI summary
A conductive adhesive includes a substrate and a conductive filler, where the substrate includes modified epoxy resin, polyurethane, and polyimide. The conductive adhesive can replace laser welding and is used in the electrochemical apparatus, so that production efficiency of the electrochemical apparatus can be improved, and quality of the electrochemical apparatus is also improved.