Zinc Electrode Separators with Resistive Layers for Uniform Current
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Solution Overview
Problem
Storage batteries with zinc negative electrodes suffer from short cycling life due to zinc distortion caused by non-uniform current density distribution and high solubility of zinc products in alkaline electrolytes, which leads to reduced capacity and premature battery degradation.
Innovation Solution
Enhanced separators with a separator layer and one or more resistive layers, where the dimensions of the resistive layers are less than or equal to the separator layer, and treated with PTFE suspension to increase resistance, particularly at the edges, to achieve a more uniform current density distribution and reduce zinc electrode distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the separator layer is made thicker to reduce zinc distortion, then the current density distribution becomes more uniform, but the battery internal resistance increases and capacity is reduced
Solution Approach 1:
The separator is divided into multiple functional layers: a base separator layer and additional resistive layers positioned at specific locations (edges or center). This segmentation allows different regions to have different resistance characteristics, achieving uniform current distribution without uniformly increasing the entire separator thickness, thus avoiding excessive internal resistance.
Solution Approach 2:
Resistive layers are selectively positioned at specific locations (edges or center of the separator) rather than uniformly distributed. This local quality approach modifies current density distribution precisely where needed to prevent zinc distortion, while minimizing the overall impact on battery internal resistance and capacity.
2Stability of the object's composition
If additional resistive layers are added to the separator to improve current density uniformity, then zinc distortion is reduced, but the device complexity and manufacturing cost increase
Solution Approach 1:
The separator structure is segmented into a base layer and optional additional resistive layers. This allows the system to maintain simplicity (single layer) when zinc distortion is not problematic, and only add complexity (multiple layers) when needed to solve the distortion issue, making the complexity adaptive rather than mandatory.
Solution Approach 2:
Instead of uniformly increasing separator thickness or adding resistive layers across the entire separator surface, the invention applies resistive layers only in specific regions (edges or center) where they are most effective. This partial action achieves the desired current distribution improvement with minimal additional complexity.
3Stability of the object's composition
If the separator is designed with higher resistance at edges to reduce current density at edges, then zinc distortion is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The separator is segmented into distinct functional zones with resistive layers positioned at specific locations (edges or center). This segmentation creates clear manufacturing targets for layer placement, making it easier to control positioning precision compared to requiring uniform thickness variations across the entire separator surface.
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 enhanced separators effectively reduce zinc electrode distortion, prolong battery life, and maintain capacity by ensuring a uniform current density distribution, making the batteries simpler, cost-effective, and suitable for smaller cylindrical batteries.
Implementation Method 1
treated with a PTFE suspension to increase resistance
Data Source
AI summary
The present invention discloses enhanced separators for storage batteries with zinc negative electrodes. These enhanced separators include a separator layer and one or more resistive layers on said separator layer. The dimensions of the one or more resistive layers are less than or equal to that of the separator layer. Portions of the separator layer can also be treated with a PTFE suspension to increase the resistance at those portions. For storage batteries where the resistance along two edges of the separator layer has to be larger then the center, the enhanced separator include said resistive layers where each layer includes two independent parts positioned along the two edges of the separator layer. The edge portions of the separator layer can also be treated with a PTFE suspension. Using these enhanced separators in storage batteries with zinc negative electrodes can increase the capacity and prolong the life of the batteries. These enhanced separators are also simple, easy to manufacture, and low in cost.