| 摘要 |
PROBLEM TO BE SOLVED: To prevent the overflow of an electrolyte caused by vibration during use and prevent the deformation or rupture caused by increase in inner pressure of a battery by forming an exhausting hole at the top of a vent plug, inclining the bottom, and installing a gas permeable film at the inclined bottom. SOLUTION: A vent plug 1 is fit to a cover 3 through a rubber gasket 2, and an exhausting hole 4 is formed at the top of the vent plug 1. The bottom of the vent plug 1 is formed at an inclined bottom 5, and an angle of inclination is made about 25 degrees or more. A gas permeable film 6 such as polytetrafluoroethylene film is fusion-bonded to the inclined bottom 5. Although oxygen gas or hydrogen gas is produced on the inside of a lead-acid battery by charging, the gas is permeated through the gas permeable film 6, then exhausted to the outside through the exhausting hole 4, and pressure increase is prevented. When vibration is applied to a lead-acid battery, dilute sulfuric acid is shaken, and strikes against the gas permeable film 6. Since the bottom is the inclined bottom 5, the force of the dilute sulfuric acid is dispersed, and increase in pressure of the sulfuric acid applied to the gas permeable film 6 is suppressed. |
