Alkaline Battery Closed Space Volume Control
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Solution Overview
Problem
High-potential electrolytic manganese dioxide used in alkaline batteries enhances initial discharge performance but deteriorates discharge performance after storage, leading to a short shelf life due to crystal distortion and reduction reactions with hydrogen gas.
Innovation Solution
Reducing the volume of the closed space between the gasket and electrodes in the battery case to 2.0% to 6.0% of the battery case volume, which suppresses the reduction reaction of manganese dioxide caused by hydrogen gas, thereby enhancing initial discharge performance and extending shelf life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-potential electrolytic manganese dioxide is used as positive electrode active material, then initial discharge performance is enhanced, but discharge performance after storage deteriorates
Solution Approach 1:
The patent changes the physical parameter of closed space volume to control the chemical reaction between hydrogen gas and manganese dioxide. By reducing the closed space volume to 6.0% or less of the battery case volume, the concentration of hydrogen gas is limited, which suppresses the reduction reaction of manganese dioxide during storage while maintaining high initial discharge performance.
2Use of energy by moving object
If high-potential electrolytic manganese dioxide is used, then energy density is increased, but shelf life is reduced
Solution Approach 1:
The patent creates a constrained environment by reducing the closed space volume, which limits the accumulation of hydrogen gas that causes harmful reduction reactions. This effectively creates a protective environment that preserves the manganese dioxide's oxidation state and maintains both high energy density and extended shelf life.
3Reliability
If closed space volume is reduced, then reduction reaction of manganese dioxide is suppressed, but battery assembly complexity increases
Solution Approach 1:
The patent specifies a quantitative parameter (closed space volume ratio of 6.0% or less) that provides a clear design target for manufacturers. This parameter-based approach simplifies the implementation process compared to qualitative descriptions, making it easier to control the reduction reaction while managing assembly complexity.
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 reduction in the closed space volume effectively maintains a high remaining percentage of discharge performance after storage, comparable to batteries using lower potential manganese dioxide, while improving initial discharge performance by reducing hydrogen gas accumulation and reaction.
Implementation Method 1
discharge performance after storage deteriorates... crystal distortion of manganese dioxide occurring when an alkaline battery using electrolytic manganese dioxide at a high potential of 270 mV or more is stored for a long time... reduction reaction of manganese dioxide caused by hydrogen gas
Data Source
AI summary
The opening portion of a battery case 1 is sealed with a sealing plate 7 using a gasket 5. The potential of electrolytic manganese dioxide in a positive electrode active material is in the range from 275 to 320 mV. The volume of a closed space formed between the gasket 5 and positive and negative electrodes 2 and 3 in the battery case 1 is in the range from 2.0 to 6.0% of the volume inside the battery formed by the battery case 1 and the sealing plate 7.