Zinc-Air Cell External Electrolyte Management
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Solution Overview
Problem
Rechargeable zinc-air batteries face challenges with energy density, cycle life, and compactness due to zinc dendrite formation, electrolyte redistribution, and limited air electrode durability, leading to low energy densities and mechanical issues during charge-discharge cycling.
Innovation Solution
A zinc-air cell and recharging apparatus with a zinc-containing electrolyte reservoir, fluid drainer, and pumping system that allows for external electrolyte management, minimizing zinc and electrolyte within the cell, and using a porous structure and electrocatalyst to prevent zinc buildup, enabling efficient recharging and high energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the battery is recharged solely by application of electric current, then the battery can be recharged, but the zinc electrode does not maintain a compact shape on repeated charge-discharge cycling, forming zinc dendrites or undergoing zinc shape change
Solution Approach 1:
The patent extracts the harmful zinc dendrites and redistributed zinc from the cell by draining the electrolyte off-board and removing the zinc-containing structures, then replaces them with fresh zinc anodes. This external removal process prevents dendrite accumulation and shape change within the cell, resolving the reliability issue while maintaining cycle life.
Solution Approach 2:
The patent changes the physical state and location of zinc management by moving from in-cell zinc maintenance to off-board zinc processing. By draining electrolyte containing dissolved zinc and dendrites externally and replacing anodes off-board, the system maintains electrode shape stability while enabling repeated cycling.
2Duration of action of moving object
If the battery uses excess zinc and excess electrolyte to prolong cycle life, then the cycle life is extended, but the energy density decreases to around 100-150 Wh/kg
Solution Approach 1:
The patent discards spent zinc anodes and electrolyte off-board after they have served their purpose, then recovers them through external processing. This allows the cell to operate with minimal zinc and electrolyte quantities during discharge, achieving high energy density, while the discarded materials are regenerated externally to extend cycle life without compromising energy density.
3Duration of action of moving object
If the battery is designed as a disassembly-structured system with replaceable anodes, then the cycle life is extended, but electrolyte leakage is difficult to prevent and the system complexity increases
Solution Approach 1:
The patent segments the battery system into a sealed cell unit and an external processing system. The cell itself remains compact and sealed with minimal components, while the complex functions of zinc regeneration and electrolyte processing are separated into external equipment. This segmentation maintains simple cell structure while enabling extended cycle life through off-board maintenance.
4Ease of manufacture
If the air electrode is based on carbon bonded by polymer, then the battery can function, but the air electrode has limited life when exposed to the rigors of charge-discharge cycling, especially on erosive oxygen evolution on charge
Solution Approach 1:
The patent changes the operational parameters of the air electrode by removing it from exposure to extreme conditions through the electrolyte drainage process. By draining the electrolyte off-board where oxygen evolution occurs outside the cell, the air electrode is protected from erosive conditions, extending its cycle life while maintaining manufacturability.
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 improved energy density (up to 350Wh/kg) and compact design by maintaining zinc in a pristine state and minimizing auxiliary components, allowing for efficient recharging and extended cycle life with reduced mechanical stress.
Implementation Method 1
at least one porous structure capable of absorbing oxygen from the air as the cathode of said cell
Implementation Method 2
an outer coating, mesh or wire assembly positioned proximally to said porous polymer-based mat and distal to said porous support and comprising an electrocatalyst for hydrogen evolution in the presence of zinc
Implementation Method 3
at least one pumping element, which pumping element facilitates delivery of said zinc-containing alkaline electrolyte fluid from said reservoir to said zinc-air cell
Implementation Method 4
said fluid drainer is operationally connectible to said device containing said zinc-air cell or zinc-air battery and facilitates draining of at least a portion of an electrolyte fluid located in a discharged or not fully charged zinc-air cell or zinc-air battery
Data Source
Figure 1
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Figure 3~4
AI summary
A zinc-air cell comprising a zinc-containing anode, comprising at least one electro-conducting porous support for zinc incorporation therewithin, and a porous polymer-based mat positioned proximally to said porous support, at least one porous structure capable of absorbing oxygen from the air as the cathode of said cell, a casing in which said anode and cathode are positioned, said casing further comprising an alkaline electrolyte fluid, and an inlet and outlet in said casing, wherein said inlet and outlet are constructed so as to permit exchange of said electrolyte fluid in said cell with an electrolyte fluid located in an external reservoir, wherein said anode and cathode are electrically connectible across a load.