AA Alkaline Battery Separator Porosity for Lower In-Cell Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for alkaline batteries with optimized integrated in-cell resistances to enhance power capability and service life, as existing batteries face limitations in increasing electrochemically active material loading due to fixed external dimensions and constrained internal volumes.
Innovation Solution
A primary AA alkaline battery design incorporating an anode, cathode, and electrolyte with potassium hydroxide, featuring an electrochemically active cathode material of electrolytic manganese dioxide and a separator with high porosity, along with a method to determine integrated in-cell resistances by measuring electrolyte and battery resistances at different temperatures, allowing for calculation of integrated in-cell ionic and electronic resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If higher loading of electrochemically active anode and/or cathode materials is used, then battery capacity and service life are improved, but battery internal volume constraint is exceeded
Solution Approach 1:
The patent employs porous cathode material with controlled porosity (30-70%) to increase the surface area and volume available for electrochemically active material within the constrained battery internal volume. This allows higher loading of active materials without exceeding the fixed external dimensions, thereby improving capacity and service life while maintaining volume constraints
Solution Approach 2:
The patent optimizes multiple parameters including cathode material porosity (30-70%), cathode loading density (2.5-3.5 g/cm³), and separator porosity (40-80%) to maximize the amount of electrochemically active material within the constrained volume. These parameter adjustments enable higher material loading while maintaining acceptable internal resistance and discharge performance
2Volume of moving object
If battery internal volume is constrained to common sizes, then battery dimensions are standardized, but electrochemically active material loading is limited
Solution Approach 1:
By using porous cathode material with porosity between 30-70%, the patent increases the effective volume available for active material within the standardized battery shell. This allows more electrochemically active material to be packed into the same external dimensions, overcoming the limitation of fixed battery sizes
Solution Approach 2:
The patent utilizes the porosity dimension of the cathode material to increase material loading. By creating a three-dimensional porous structure rather than a dense compact, the effective volume for active material is expanded without increasing the external battery dimensions
3Power
If integrated in-cell resistances are reduced, then power capability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent reduces integrated in-cell resistance by optimizing parameters such as cathode loading density (2.5-3.5 g/cm³), separator porosity (40-80%), and electrolyte composition. These parameter adjustments improve ionic conductivity and reduce resistance without requiring complex manufacturing processes, maintaining compatibility with existing production methods
Solution Approach 2:
The patent uses composite cathode material consisting of electrolytic manganese dioxide combined with conductive additives and binders in specific ratios. This composite structure improves electronic and ionic conductivity, reducing overall cell resistance while using standard manufacturing techniques
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 battery achieves reduced integrated in-cell resistances, improving discharge performance and extending service life by optimizing the distribution and conductivity of electrochemically active materials within the constrained battery volume.
Implementation Method 1
The electrolyte contains ions that flow through the separator between the anode and cathode to maintain charge balance throughout the battery during discharge
Implementation Method 2
The anode contains an electrochemically active anode material that can be oxidized
Implementation Method 3
The cathode contains an electrochemically active cathode material that can be reduced
Implementation Method 4
The separator has a porosity of greater than 75%
Data Source
AI summary
The invention is directed toward a primary AA alkaline battery. The primary AA alkaline battery includes an anode; a cathode; an electrolyte; and a separator between the anode and the cathode. The anode includes an electrochemically active anode material. The cathode includes an electrochemically active cathode material. The electrolyte includes potassium hydroxide. The primary AA alkaline battery has an integrated in-cell ionic resistance (Ri) at 22° C. of less than about 39 mΩ. The separator has a porosity of greater than 70%.