Zinc Battery Negative Electrode Layout for Lower Self-Discharge
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Solution Overview
Problem
Zinc batteries suffer from significant self-discharge due to the spontaneous dissolution of metallic zinc at the outermost peripheral portion of the negative electrode, leading to local cell reactions with the electrolyte and the inner wall of the outer can.
Innovation Solution
The negative electrode is designed with a non-porous current collector and a mixture layer that exposes the current collector at the outermost peripheral surface, preventing direct contact with the electrolyte and reducing local cell reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the negative electrode is disposed at the outermost peripheral surface of the wound body, then the battery structure is simplified and manufacturing is easier, but self-discharge increases due to direct contact between zinc and the outer can
Solution Approach 1:
The negative electrode is segmented into two distinct parts: a zinc-containing negative electrode mixture layer and an exposed current collector portion. This segmentation allows the zinc to be isolated from direct contact with the outer can while maintaining the simplified winding structure, thus reducing self-discharge without complicating manufacturing.
Solution Approach 2:
The harmful zinc-containing mixture layer is extracted or removed from the outermost peripheral surface, leaving only the current collector exposed at the outer can interface. This eliminates the direct contact between zinc and the outer can that causes self-discharge, while preserving the ease of manufacturing the wound battery structure.
2Quantity of substance
If metallic zinc is used as the negative electrode active material, then high capacity is achieved, but spontaneous dissolution occurs leading to self-discharge
Solution Approach 1:
The current collector serves as an intermediary between the zinc-containing negative electrode mixture layer and the outer can. By exposing the current collector at the outermost surface instead of zinc, it mediates the interface interaction, preventing direct contact between zinc and the outer can environment that would cause spontaneous dissolution and self-discharge.
Solution Approach 2:
Different portions of the negative electrode are assigned different functions: the zinc-containing mixture layer provides high capacity in the interior, while the exposed current collector portion at the outermost surface provides protection against self-discharge. This local differentiation of quality allows simultaneous achievement of high capacity and low self-discharge.
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 configuration significantly reduces self-discharge by minimizing zinc ion elution and local cell reactions, thereby maintaining higher discharge capacity over time.
Implementation Method 1
a current collector exposed portion where the negative electrode mixture layer is not disposed and the current collector is exposed
Data Source
AI summary
This negative electrode for a zinc battery comprises a nonporous current collector and a negative electrode mixture layer which is held by the current collector and contains at least one of zinc, a zinc alloy, and a zinc-containing compound. The negative electrode has a current collector-exposed section in which the negative electrode mixture layer is not disposed, in a portion located at the outermost circumferential surface when wound.