Polyolefin Separator for Lead-Acid Battery Corrosion
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Solution Overview
Problem
Current polyethylene resin separators for lead-acid batteries suffer from surface active agent elution, leading to reduced battery capacity, increased electrolyte loss, and corrosion of cell joints due to the formation of organic acids, especially under high-temperature and overcharged conditions.
Innovation Solution
A porous membrane separator made from polyolefin resin, inorganic powder, and mineral oil with a controlled amount of surface active agent, ensuring minimal reducing substance liberation, thereby preventing corrosion and maintaining battery capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a polyethylene resin separator with projections and no glass mat is used, then assembly speed is improved and cost is reduced, but surface active agent elution increases causing battery capacity loss and corrosion
Solution Approach 1:
The patent changes the chemical composition parameters of the separator by incorporating specific additives (0.01-5 wt% of compounds containing carboxylic acid groups, hydroxyl groups, or amino groups) into the polyethylene resin matrix. This modification reduces surface active agent elution while maintaining the ribbed structure's assembly advantages, thereby resolving the contradiction between productivity and reliability
Solution Approach 2:
The patent creates a composite separator material by combining polyethylene resin with functional additives that have specific chemical groups (carboxylic acid, hydroxyl, or amino groups). This composite structure maintains the mechanical properties needed for quick assembly while reducing harmful elution, thus resolving the contradiction between assembly speed and battery capacity maintenance
2Ease of manufacture
If a polyethylene resin separator with projections and no glass mat is used, then manufacturing cost is reduced, but corrosion of cell joints increases due to organic acid formation
Solution Approach 1:
The patent converts the potentially harmful polyethylene resin matrix into a beneficial structure by incorporating functional additives that actively prevent corrosion. These additives (containing carboxylic acid, hydroxyl, or amino groups) neutralize organic acids before they can corrode cell joints, thus transforming the harmful effect into a protective mechanism while maintaining cost-effectiveness
Solution Approach 2:
The patent modifies the chemical parameters of the separator by adding specific functional groups (0.01-5 wt% of compounds with carboxylic acid, hydroxyl, or amino groups) to the polyethylene resin. This composition change reduces organic acid formation and corrosion while maintaining the simple, cost-effective manufacturing process
3Ease of operation
If surface active agent is added to improve wetting property, then electrolyte wettability is improved, but reducing substance liberation increases causing capacity loss and corrosion
Solution Approach 1:
The patent changes the chemical nature of the surface active agent by specifying compounds with particular functional groups (carboxylic acid, hydroxyl, or amino groups) and controlling their concentration (0.01-5 wt%). This parameter modification maintains good electrolyte wettability while significantly reducing reducing substance liberation, thus resolving the contradiction between ease of operation and reliability
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 separator maintains a predetermined battery capacity and prolongs battery life by minimizing reducing substance liberation, preventing corrosion, and enhancing discharge performance even in high-temperature environments.
Implementation Method 1
the amount of any reducing substance liberated or eluted after 24 hours of electrolysis carried out at about 25° C. with a direct current of 1.2 A
Implementation Method 2
it has essentially required a surface active agent improving its wetting property with the electrolyte
Implementation Method 3
the reducing substance liberated or produced from the separator is changed by the oxidizing power in the battery into an organic acid having a lead solubility
Data Source
AI summary
A separator for a lead-acid battery enabling the lead acid battery to infallibly have a predetermined capacity after the initial charging and a prolonged service life by limiting the maximum quantity of reducing substance liberated or produced from the separator at or below a given level.The separator for a lead-acid battery comprising a porous membrane made mainly from a polyolefin resin, an inorganic powder and a mineral oil and containing a surface active agent as an auxiliary material, characterized in that the amount of any reducing substance liberated or eluted after 24 hours of electrolysis carried out at about 25° C. with a direct current of 1.2 A by using an electrolytic cell composed of the porous membrane, a positive electrode, a negative electrode and diluted sulfuric acid is 1.0 ml or less per 100 cm2 when calculated from the consumption of a (1/100)N potassium permanganate solution per 100 cm2 of the porous membrane.