Flexible Metal Substrate Positive Electrode for Alkaline Battery
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Solution Overview
Problem
The existing positive electrodes for alkaline secondary batteries, particularly those using foamed nickel, face challenges in reducing film thickness, improving output properties, and extending cycle life due to high costs and limited conductivity.
Innovation Solution
A positive electrode is developed by laminating a flexible metal substrate with a conductivity primer layer and a composite material layer containing active materials, binder resin, and conductive materials, enhancing current collection and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If foamed nickel is used as a collector, then electrical conductivity is improved, but cost increases and film thickness reduction becomes difficult
Solution Approach 1:
The patent uses a composite structure consisting of a metal substrate (steel or aluminum foil) combined with a conductive coating layer (nickel, copper, or aluminum). This composite approach provides the necessary electrical conductivity through the conductive layer while the thin metal substrate enables reduced film thickness and lower cost compared to using thick foamed nickel throughout.
Solution Approach 2:
The conductive properties are localized to the coating layer applied on the substrate surface, rather than requiring the entire substrate to be made of expensive foamed nickel. The metal substrate provides mechanical support while the thin conductive coating provides the necessary electrical conductivity, achieving local optimization of properties.
2Ease of manufacture
If foil-like substrate is used instead of foamed nickel, then cost is reduced, but current collection and interface adhesion deteriorate
Solution Approach 1:
The patent applies a conductive coating layer (nickel, copper, or aluminum) on the metal substrate surface to enhance current collection capability and interface adhesion. This coating layer compensates for the inferior conductivity and adhesion properties of the thin metal substrate, solving the reliability issues while maintaining cost advantages.
Solution Approach 2:
The patent changes the surface properties of the metal substrate by applying conductive coatings, thereby modifying parameters such as electrical conductivity and surface adhesion. This allows the thin substrate to achieve performance levels comparable to or better than foamed nickel in terms of current collection and interface bonding.
3Productivity
If large current charging is performed, then rapid charging capability is improved, but output performance requirements increase
Solution Approach 1:
The conductive coating layer on the metal substrate creates an efficient current collection network that can handle large charging currents. The composite structure with its optimized conductivity distribution enables rapid charging while maintaining the power output performance needed for vehicle applications.
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
This configuration results in improved output properties and cycle life for alkaline secondary batteries, enabling efficient rapid charging and discharging while maintaining durability.
Implementation Method 1
The cobalt hydroxide, cobalt oxide, and the like are changed to cobalt oxyhydroxide in charging to exhibit high electrical conductivity to form a fine conductive network between nickel hydroxide particles
Data Source
AI summary
There is provided a positive electrode for an alkaline secondary battery and an alkaline secondary battery having good output properties and cycle life. To that end, a positive electrode (10) for alkaline secondary battery is obtained by laminating a flexible metal substrate (11) having flexibility; a primer layer (12) having conductivity provided on one or both surfaces of the substrate (11); and a positive electrode composite material layer (13) provided on the primer layer (12) and containing a positive electrode active material, a binder resin, and a first conductive material.