Brass Current Collector Crystal Size for Battery Leakage
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Solution Overview
Problem
Alkaline dry batteries experience electrolyte leakage due to hydrogen gas generation during overdischarge, particularly in assembled batteries with polarity reversal, where the leaching of metals from the negative electrode current collector increases internal pressure, leading to safety valve activation and leakage, and existing solutions are insufficient to prevent this issue.
Innovation Solution
The use of a negative electrode current collector made of brass with an average crystal particle size ranging from 0.015 mm to 0.054 mm and a zinc content of 30 to 40 wt%, which reduces the leaching of metals during overdischarge and thereby minimizes hydrogen gas generation, enhancing electrolyte leakage resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If plating the surface of brass with zinc, tin, or lead is used to inhibit hydrogen gas generation, then hydrogen gas generation is reduced, but the complexity of the current collector structure increases and manufacturing cost rises
Solution Approach 1:
The invention extracts and eliminates the plating layer from the current collector structure, using unplated brass instead. This removes the harmful effect of metal leaching that occurs with plated structures during polarity reversal, while simplifying the overall structure by eliminating the plating process entirely.
Solution Approach 2:
The invention changes the material parameters by specifying brass with 20-40 wt% zinc content and controlling the crystal particle size to 0.015-0.054 mm. These parameter changes enable the brass to resist leaching during polarity reversal without requiring additional plating layers, thus reducing structure complexity while maintaining hydrogen gas suppression.
2Ease of manufacture
If using conventional brass current collector, then manufacturing is simple, but metal leaching occurs during polarity reversal leading to electrolyte leakage
Solution Approach 1:
The invention modifies the brass material parameters by controlling zinc content (20-40 wt%) and crystal particle size (0.015-0.054 mm). These parameter changes enhance the brass's resistance to leaching during polarity reversal, improving reliability without complicating the manufacturing process.
Solution Approach 2:
The invention uses a composite brass alloy with specific zinc content rather than pure copper or simple brass. This composite material composition provides both ease of manufacture and superior resistance to leaching during polarity reversal, preventing electrolyte leakage while maintaining manufacturing simplicity.
3Reliability
If increasing the zinc content in brass to reduce leaching, then electrolyte leakage resistance improves, but the mechanical strength and flexibility of the current collector may deteriorate
Solution Approach 1:
The invention optimizes the zinc content parameter within the range of 20-40 wt%, finding the optimal balance between leaching resistance and mechanical strength. This parameter optimization ensures sufficient electrolyte leakage resistance while maintaining the necessary mechanical strength and flexibility for current collector functionality.
Solution Approach 2:
The invention employs a composite brass alloy with controlled zinc content that balances the competing requirements of leaching resistance and mechanical strength. The specific composition range (20-40 wt% zinc) provides both protective properties and structural integrity without requiring additional reinforcing elements.
4Object-generated harmful factors
If controlling the crystal particle size of brass to reduce leaching, then hydrogen gas generation decreases, but the manufacturing precision requirements increase
Solution Approach 1:
The invention specifies a crystal particle size range of 0.015-0.054 mm that effectively reduces leaching and hydrogen gas generation. This parameter specification balances the need for reduced harmful effects with achievable manufacturing precision, avoiding excessively tight tolerances that would complicate production.
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 significantly reduces gas generation during overdischarge, improves electrolyte leakage resistance, and increases the flexibility and productivity of the battery production process by inhibiting metal leaching from the negative electrode current collector, thus preventing premature battery failure and ensuring reliable operation.
Implementation Method 1
the leaching of the constituent elements of the negative electrode current collector into the electrolyte is considered to be involved in the mechanism of the hydrogen gas generation
Implementation Method 2
When an alkaline dry battery is in an overdischarged state, hydrogen gas is generated in the battery, thus possibly causing leaking of the electrolyte
Data Source
Figure 1
AI summary
An alkaline dry battery according to the invention includes a hollow cylindrical positive electrode mixture including a positive electrode active material; a gelled negative electrode filled into the hollow of the positive electrode mixture and including a negative electrode active material; a separator disposed between the positive electrode mixture and the gelled negative electrode; a negative electrode current collector inserted into the gelled negative electrode; a negative electrode terminal plate electrically connected to the negative electrode current collector; and an electrolyte. The negative electrode current collector includes brass having an average crystal particle size of 0.015 mm or greater.