Alkaline Battery Positive Electrode Sulfate Control
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Solution Overview
Problem
Alkaline storage batteries face reduced charge efficiency and capacity at high temperatures due to oxygen production at the positive electrode, inhibiting the conversion of nickel hydroxide to nickel oxyhydroxide and leading to self-discharge, which is problematic for applications like hybrid vehicles requiring high efficiency over a wide temperature range.
Innovation Solution
A positive electrode for alkaline storage batteries is developed, incorporating nickel oxide with specific additives such as ytterbium, indium, and titanium, along with controlled sulfate ion levels (0.45 mass % or less), which suppresses oxygen production and enhances the utilization rate of the positive electrode active material, even at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an alkaline storage battery is charged at a high temperature, then oxygen is produced at the positive electrode, but conversion from nickel hydroxide to nickel oxyhydroxide is inhibited and charge efficiency lowers
Solution Approach 1:
The invention changes the chemical composition parameters of the positive electrode by adding specific metal elements (Y, In, Sb, Ba, Ca, Be) to the nickel oxide system. This modifies the electrochemical properties of the positive electrode, enabling it to maintain high charge efficiency across a wide temperature range including high temperatures by suppressing oxygen evolution and facilitating the nickel hydroxide to nickel oxyhydroxide conversion.
Solution Approach 2:
The invention creates a composite positive electrode material consisting of nickel oxide combined with multiple metal elements (Y, In, Sb, Ba, Ca, Be). This composite structure leverages the synergistic effects of different metals to improve overall battery performance, particularly charge efficiency at high temperatures, by combining the benefits of each metallic component in the nickel oxide matrix.
2Adaptability or versatility
If an alkaline storage battery operates at a high temperature, then self-discharge increases and battery capacity lowers, but operation over a wide temperature range is required for hybrid vehicle applications
Solution Approach 1:
The invention modifies the chemical composition parameters of the positive electrode by incorporating multiple metal elements into the nickel oxide system. This compositional change enables the battery to adapt to a wide temperature range by stabilizing the electrochemical reactions and reducing self-discharge, particularly at high temperatures where self-discharge normally increases.
Solution Approach 2:
The invention introduces specific metal elements (Y, In, Sb, Ba, Ca, Be) at controlled concentrations into the nickel oxide positive electrode. This creates local compositional variations that optimize electrochemical performance at different temperatures, allowing the battery to maintain low self-discharge and high capacity across the required temperature range for hybrid 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
The solution achieves high charge efficiency and reduced self-discharge across a wide temperature range, maintaining battery performance and capacity, especially in hybrid vehicle applications.
Implementation Method 1
during charge, nickel hydroxide is converted into nickel oxyhydroxide, and during discharge, nickel oxyhydroxide is converted into nickel hydroxide
Implementation Method 2
the amount of sulfate ions SO4 2− incorporated into the nickel oxide
Data Source
AI summary
Provided is a positive electrode for an alkaline storage battery, capable of achieving a high charge efficiency over a wide range of temperature including high temperatures. The positive electrode includes a positive electrode material mixture including: a nickel oxide as a positive electrode active material; a first additive; and a second additive differing from the first additive. An amount of sulfate ions SO42− remaining in the nickel oxide is 0.45 mass % or less. The first additive is a compound including at least one selected from the group consisting of ytterbium, indium, calcium, barium, beryllium, antimony, erbium, thulium, and lutetium. The second additive is a compound including at least one selected from the group consisting of titanium, vanadium, scandium, niobium, zirconium, and zinc.