Negative Electrode Base Member for Lithium Ion Battery
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Solution Overview
Problem
Current battery technologies face challenges in achieving high output voltage, high energy density, and superior charge and discharge cycle characteristics due to issues like irreversible deformation and detachment of negative electrode materials during lithium storage and release.
Innovation Solution
A negative electrode base member is developed with a metal film laminated on an organic film, which includes a composite film formed by compounding organic and inorganic components, and a metal oxide film, using a photoresist composition with an alkali-soluble resin and a quinone diazide group-containing compound to enhance mechanical strength and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a silicon thin film is used as negative electrode material to achieve high energy density, then the battery capacity increases, but the negative electrode material undergoes irreversible deformation and detachment during charge and discharge cycles
Solution Approach 1:
The patent applies the nesting principle by creating a multi-layered structure where the silicon thin film is embedded within a porous coating layer that is itself supported on the collector. This nested configuration allows the silicon film to expand and contract within the porous matrix during lithium insertion/extraction, preventing direct contact between the collector and silicon film, thereby eliminating irreversible deformation and detachment while maintaining high battery capacity
Solution Approach 2:
The patent employs composite materials by combining the silicon thin film with a porous coating layer formed from metal oxide particles and binder. This composite structure provides mechanical support to the silicon film during volume changes, while the porous nature of the coating allows lithium ion transport. The combination achieves both high capacity (from silicon) and good cycle stability (from the composite structure)
2Strength
If a collector with high mechanical strength is used to prevent deformation, then the structural stability improves, but the adhesion between collector and negative electrode material layer becomes insufficient
Solution Approach 1:
The patent applies the intermediary principle by introducing a porous coating layer as a mediator between the collector and the silicon thin film. This intermediate layer, composed of metal oxide particles and binder, provides both mechanical support and adequate adhesion. The porous coating transfers stresses during lithium insertion/extraction away from the collector-silicon interface, preventing detachment while maintaining structural stability
Solution Approach 2:
The porous coating layer itself is a composite material consisting of metal oxide particles (providing mechanical strength and porosity) and binder (providing adhesion). This composite structure achieves the dual requirement of mechanical support and adequate bonding to the collector, solving the contradiction between strength and adhesion
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 batteries with improved output voltage, energy density, and charge/discharge cycle characteristics by reducing stress and deformation, preventing detachment, and maintaining the integrity of the negative electrode material.
Implementation Method 1
a photoresist composition with an alkali-soluble resin and a quinone diazide group-containing compound
Data Source
AI summary
A battery having high output voltage, high energy density and excellent charge and discharge cycle characteristics is achieved through the use of one of the following negative electrode base members as a negative electrode base member for lithium ion secondary batteries: a negative electrode base member where a metal film is formed on a support having an organic film; such a negative electrode base member where the surface layer of the organic film is covered with a metal oxide film; a negative electrode base member where a metal film is formed on a support having a composite film formed from a composite film-forming material containing an organic component and an inorganic component; and a negative electrode base member where a silica coating is formed, on a support having a photoresist pattern, from a silica film-forming coating liquid and a metal film is formed on the support after removing the photoresist pattern.