Alkaline Pouch Cell Coated Terminals Prevent Electrolyte Creepage
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Solution Overview
Problem
Alkaline batteries are limited by rigid and heavy outer cases that restrict their applications and reduce specific energy and energy density due to electrolyte leakage and degradation, which is exacerbated by the failure of sealing around electrode tabs.
Innovation Solution
A lightweight, flexible pouch design with lacquer-coated negative tabs and acrylic paint-coated positive tabs, sealed using synthetic rubber and ionomer resins, eliminates electrolyte creepage and provides a hermetic seal, allowing for long-life, leak-free alkaline pouch cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid and heavy outer case is used to confine the electrode stack and electrolyte, then the battery structure is stable and sealing is provided, but the specific energy and energy density are reduced and applications are restricted
Solution Approach 1:
The patent replaces the traditional rigid metal outer case with a flexible pouch structure made of thin film materials. The pouch encapsulates the electrode stack and electrolyte, providing containment while significantly reducing weight. The pouch design maintains sealing integrity through specialized sealing structures at the tabs and edges, enabling the battery to achieve both lightweight construction and reliable containment.
2Reliability
If a rigid and heavy outer case is used to confine the electrode stack and electrolyte, then the battery structure is stable and sealing is provided, but the specific energy and energy density are reduced
Solution Approach 1:
The flexible pouch structure eliminates the need for thick rigid casing walls, allowing more of the battery volume to be occupied by active materials (electrodes and electrolyte). This increases the quantity of active substance per unit volume, thereby improving specific energy and energy density while maintaining adequate sealing through the pouch design.
3Device complexity
If traditional sealing methods are used around electrode tabs, then the structure is simple, but electrolyte creepage and degradation occur
Solution Approach 1:
The patent applies coatings to the tabs before assembly and uses pre-formed sealing structures (such as gaskets or sealed flanges) that are integrated into the pouch construction. This preliminary preparation ensures that when the tabs penetrate the pouch, the sealing is already in place, preventing electrolyte creepage along the tab surfaces and maintaining electrolyte containment without requiring complex post-assembly sealing mechanisms.
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 enhances specific energy and energy density while enabling flexible applications by preventing electrolyte leakage and degradation, achieving over 95% capacity retention in nickel-zinc alkaline chemistry tests.
Implementation Method 1
The first tab has thereon a coating including acrylic paint and the second tab has thereon a coating including lacquer to discourage creepage of the alkaline electrolyte along the first and second tabs
Data Source
AI summary
A battery cell includes an electrode assembly having a negative electrode, positive electrode, and separator bathed in an alkaline electrolyte, a pouch encapsulating the electrode assembly, and first and second tabs respectively extending from the positive and negative electrodes through the pouch. The first tab has thereon a coating including acrylic paint and the second tab has thereon a coating including lacquer to discourage creepage of the alkaline electrolyte along the first and second tabs and out of the pouch.