Lead-Acid Battery Vent Plug Layout for Electrolyte Leak Prevention

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Solution Overview

Problem

Lead-acid batteries generate oxygen and hydrogen gas during charging, causing the electrolyte solution level to rise, which can lead to leakage through the vent plug due to the increased overall length of the vent plug when a catalytic device is integrated, especially when arranged vertically or inclined.

Innovation Solution

The vent plug is designed with a tubular structure containing multiple catalytic devices arranged vertically or inclined with respect to the plug body, ensuring they are at the same height, reducing the overall length and maintaining catalytic performance by allowing recombined water to flow back into the battery container.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a catalytic device is arranged vertically or inclined inside the vent plug, then the catalytic performance is improved and water recombination is enhanced, but the overall length of the vent plug increases, causing the liquid level to reach the vent plug and leading to electrolyte solution leakage

Engineering Contradiction:
Improvecatalytic performanceVSAvoidoverall length of vent plug
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The catalytic device is arranged in an inclined or vertical orientation within the vent plug structure, utilizing the vertical dimension to achieve catalytic function while managing the spatial constraints. This dimensional arrangement allows the catalytic surface to be positioned effectively without simply extending the horizontal length of the vent plug.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The catalytic device is nested within the vent plug structure, with the catalytic element housed inside the vent plug body. This nesting approach allows the catalytic function to be integrated into the existing vent plug geometry, maximizing space utilization and minimizing the overall length extension.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Productivity

If the overall length of the vent plug is increased to accommodate a vertically arranged catalytic device, then catalytic efficiency is improved, but the distance from the liquid level to the vent plug is reduced, causing electrolyte solution to flow along the interior and leak out

Engineering Contradiction:
Improvecatalytic efficiencyVSAvoidelectrolyte solution containment
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The vent plug design incorporates a preliminary barrier or structural feature that prevents electrolyte solution from reaching the catalytic device even when the liquid level rises. This anti-action is built into the structure before leakage can occur, maintaining both catalytic efficiency and electrolyte containment reliability.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The vent plug structure employs asymmetric design elements, such as an inclined arrangement of the catalytic device or uneven internal geometry, to create a functional gradient that separates the catalytic zone from the electrolyte zone. This asymmetry allows the liquid level to rise without compromising the catalytic function or causing leakage.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If multiple catalytic devices are arranged in the vent plug, then the catalytic performance is enhanced, but the device complexity and overall length increase

Engineering Contradiction:
Improvecatalytic performanceVSAvoidvent plug structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple catalytic devices are merged or integrated into a single unified structure within the vent plug, rather than being separate components. This combining approach enhances catalytic performance while minimizing the increase in device complexity and overall length by consolidating the catalytic elements into a compact arrangement.

Inventive Principle:
Principle #5Merging (Combining)

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 effectively prevents electrolyte solution leakage while maintaining catalytic efficiency by ensuring a sufficient distance from the liquid level to the vent plug, even during rises in electrolyte level, and allows efficient gas recombination.

Implementation Method 1

a catalyst layer that contains a catalyst that promotes reaction of oxygen and hydrogen to generate water or water vapor

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

a permeable membrane covering the front surface of the catalyst layer and allowing gas to pass through

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 3

Each of the plurality of catalytic devices are arranged vertically or inclined with respect to the plug body so that the front surface of the permeable membrane has an angle with respect to a horizontal direction

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP4712198A1Lead acid battery, and liquid plug for lead acid batteries
Publication Date: 2026.03.18 GS YUASA INT LTD
  • EP4712198A1 patent drawingFigure 1
  • EP4712198A1 patent drawingFigure 2
  • EP4712198A1 patent drawingFigure 3

AI summary

A lead-acid battery 1 includes: a battery case 10; electrode plates 30A and 30B housed in the battery case 10; an electrolyte solution U housed in the battery case 10; and a vent plug 70 attached to the battery case 10, in which the vent plug 70 includes a tubular plug body 71, a splash guard 90 positioned inside the plug body, and a plurality of catalytic devices 100A, 100B, that promote reaction generating water from gas produced by charge-discharge reaction. Each of the plurality of catalytic devices 100A, 100B include a tubular case 110 with an open front surface, a catalyst layer 120 housed in the case 110, and a permeable membrane 130 covering a front surface of the catalyst layer and allowing gas to pass through. Each of the plurality of catalytic devices 100A, 100B are arranged vertically or inclined with respect to the plug body 71 so that a front surface provided with the permeable membrane 130 has an angle with respect to a horizontal direction. In an up-down direction, either all or at least a part of the plurality of catalytic devices 100A, 100B is arranged at the same height.