Alkaline Battery Case Nickel Plating Fe Exposure Control
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Solution Overview
Problem
Alkaline batteries with nickel plated steel cases face issues with Fe exposure leading to oxide coating formation, increased internal resistance, local cell formation, and degradation of discharge characteristics, which conventional methods fail to adequately address, resulting in poor leakage-resistance and storage characteristics.
Innovation Solution
Controlling the nickel plating layer on the inner surface of the battery case using electron probe microanalysis to maintain a specific intensity ratio of Fe to Ni (IFe/Ni) and existence rate of Fe-exposed areas, minimizing Fe exposure and thereby reducing oxide coating and local cell formation, thus enhancing leakage-resistance and storage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the thickness of the nickel plating layer is reduced to cut costs, then manufacturing cost decreases, but Fe exposed areas increase leading to oxide coating formation and degradation of discharge characteristics
Solution Approach 1:
The invention changes the chemical composition parameters of the nickel plating layer by introducing chromium elements and controlling the Fe/Ni intensity ratio. This allows the plating layer to maintain adequate thickness for cost-effectiveness while achieving superior corrosion resistance and preventing Fe exposure, thereby resolving the contradiction between manufacturing cost and discharge characteristics
Solution Approach 2:
The invention creates a composite plating layer structure containing nickel, chromium, and controlled iron content. This composite material approach allows the plating layer to combine the cost-effectiveness of thinner application with the protective properties of chromium, preventing oxide coating formation while reducing manufacturing costs
2Reliability
If Fe exposed areas are present on the battery case inner surface, then oxide coating forms and internal resistance increases, but controlling Fe exposure adequately requires complex plating processes
Solution Approach 1:
The invention simplifies the plating process by focusing on controlling key parameters: the Fe/Ni intensity ratio and chromium content. This parameter-based approach replaces complex multi-step processes with a more straightforward method that achieves the same protective effect against oxide coating formation and internal resistance increase
3Reliability
If Fe ions dissolve and deposit on zinc surface to form local cells, then hydrogen gas is produced reducing positive electrode materials, but preventing this requires suppressing Fe exposure
Solution Approach 1:
The invention converts the potentially harmful Fe ions into a beneficial configuration by controlling them within the plating layer structure. The controlled Fe/Ni ratio and chromium content transform Fe from a source of local cell formation into a stabilized component that prevents hydrogen gas production and capacity loss
Solution Approach 2:
Chromium acts as an intermediary element in the plating layer, mediating between the steel substrate and the electrolyte environment. This intermediary layer prevents Fe ion dissolution and migration to the zinc surface, thereby preventing local cell formation while maintaining battery capacity
4Reliability
If gas builds up from local cell formation, then inner pressure rises actuating the explosion-proof valve, but preventing gas buildup requires preventing Fe exposure
Solution Approach 1:
The invention provides beforehand cushioning by incorporating chromium and controlling Fe/Ni ratios in the plating layer before any harmful reactions can occur. This preventive measure cushions against Fe ion dissolution and subsequent gas formation, maintaining leakage-resistance characteristics and preventing dangerous pressure buildup
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 controlled nickel plating layer significantly improves the leakage-resistance and storage characteristics of alkaline batteries by minimizing Fe exposure, maintaining low internal resistance, and preventing gas buildup, leading to better discharge performance and reduced risk of leakage.
Implementation Method 1
The battery case comprises a nickel plated steel plate having a nickel plating layer at least on the inner surface
Implementation Method 2
electron probe microanalysis... in which a substance sample is irradiated with an accelerated electron beam to detect and identify elements
Data Source
AI summary
An electrochemical device, such as an alkaline battery, that is excellent in leakage-resistance and storage characteristics is provided by controlling at least one of the following two conditions with respect to at least the inner side surface of a battery case comprising a nickel plated steel plate. The two conditions are: (1) the intensity ratio of Fe to Ni (IFe/Ni) as determined by electron probe microanalysis; and (2) the ratio of the area with an intensity ratio of Fe to Ni (IFe/Ni) of greater than 1.0 as determined by electron probe microanalysis to the whole area.