Gelled Negative Electrode Non-Benzene Solvent Polymerization
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Solution Overview
Problem
The use of non-benzene solvents in polymerizing gelling agents for alkaline batteries results in lower viscosity gelled negative electrodes, leading to alkaline electrolyte separation and increased manufacturing costs, as well as potential internal short-circuits due to non-uniform filling and increased flowability, which degrades battery performance.
Innovation Solution
A gelled negative electrode for alkaline batteries is formed using a cross-linked poly(meth)acrylic acid or salt polymerized in a non-benzene solvent, with a specific surface area of zinc powder between 0.025 and 0.045 m2/g, and a low-polar or non-polar hydrocarbon-based solvent like n-hexane or cyclohexane, to enhance electrolyte retention and prevent internal short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a gelling agent is polymerized in a non-benzene solvent, then air pollution and health hazards are reduced, but the viscosity of the gelled negative electrode decreases leading to electrolyte separation
Solution Approach 1:
The patent changes the polymerization parameters by controlling the type of non-benzene solvent used (aromatic vs. aliphatic), the polymerization method, and the cross-linking degree to achieve high molecular weight polymers with sufficient viscosity while avoiding benzene's harmful effects
Solution Approach 2:
The patent uses composite gelling agents formed by cross-linking poly(meth)acrylic acid or its salts with other polymers or compounds to enhance viscosity and structural stability while maintaining the benefits of non-benzene solvent polymerization
2Quantity of substance
If the gelling agent is highly polymerized to reduce the amount needed for achieving predetermined viscosity, then the added amount of gelling agent is reduced, but the discharge characteristics of the battery may be degraded
Solution Approach 1:
The patent optimizes the polymerization parameters including monomer-to-crosslinker ratio, polymerization temperature, and solvent type to achieve the right balance between polymer molecular weight and discharge characteristics, ensuring sufficient thickening power without excessive polymerization that would harm battery performance
3Stability of the object's composition
If the gelling agent is polymerized in benzene solvent, then a highly polymerized cross-linked poly(meth)acrylic acid is obtained with high viscosity, but air pollution and health hazards increase
Solution Approach 1:
The patent extracts and eliminates the harmful benzene solvent from the polymerization process while maintaining the desired polymerization outcome by substituting it with safer non-benzene solvents that can still produce high molecular weight polymers through controlled polymerization conditions
Solution Approach 2:
The patent uses alternative solvents that are safer and more environmentally friendly, accepting that slightly different polymerization conditions may be needed, but gaining the benefit of reduced health hazards and air pollution
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 approach maintains excellent alkaline electrolyte retention, prevents internal short-circuits, and reduces manufacturing costs without increasing the number of manufacturing steps, while ensuring the battery's discharge characteristics are not compromised.
Implementation Method 1
a gelled negative electrode, which is obtained by gelling a mixture of alkaline electrolyte and zinc powder with an gelling agent added
Implementation Method 2
the gelled negative electrode is adjusted to have a predetermined viscosity for preventing the zinc powder from sedimenting in the alkaline electrolyte
Implementation Method 3
enhancing the thickening effect of the gelling agent by adding ultra-fine particles of a metal oxide to the gelling agent. This reduces the added amount of the gelling agent required for attaining the predetermined viscosity
Implementation Method 4
a cross-linked polymer formed by radical polymerization in a non-benzene solvent
Implementation Method 5
a cross-linked poly(meth)acrylic acid (or salt) formed by polymerizing a (meth)acrylic acid (or salt)
Data Source
AI summary
A gelled negative electrode contains zinc powder, alkaline electrolyte, and a gelling agent. The specific surface area of the zinc powder is in the range between 0.025 and 0.045 m2/g. The gelling agent contains, as a main component, a cross-linked polymer formed by radical polymerization in a non-benzene solvent, specifically, a cross-linked poly(meth)acrylic acid (or salt) formed by radical polymerization of a (meth)acrylic acid (or slat) in a non-benzene solvent.