Abstract: A TIG welded joint in a high-Mn content steel material that can be formed with reduced occurrence of hot cracking during the welding process and has high strength and excellent cryogenic impact toughness. In the TIG welded joint, the high-Mn content steel material has a chemical composition including, by mass %, C: 0.10 to 0.80%, Si: 0.05 to 1.00%, Mn: 18.0 to 30.0%, P: 0.030% or less, S: 0.0070% or less, Al: 0.010 to 0.070%, Cr: 2.5 to 7.0%, N: 0.0050 to 0.0500%, and O: 0.0050% or less, the balance being Fe and incidental impurities, and a weld metal has a chemical composition including C: 0.10 to 0.80%, Si: 0.05 to 1.00%, Mn: 15.0 to 30.0%, P: 0.030% or less, S: 0.030% or less, Al: 0.100% or less, Cr: 6.0 to 14.0%, and N: 0.100% or less, the balance being Fe and incidental impurities.

Abstract: A TIG welding filler metal is provided that has a composition including, by mass %, C: 0.20 to 0.80%, Si: 0.15 to 0.90%, Mn: 15.0 to 30.0%, P: 0.030% or less, S: 0.030% or less, Cr: 6.0 to 15.0%, and N: 0.120% or less, the balance being Fe and incidental impurities. Where necessary, the filler metal may contain one or two selected from Ni and Mo, may further contain one, or two or more selected from V, Ti, and Nb, and may additionally contain one, or two or more selected from Cu, Al, Ca, and REM. This configuration reduces the occurrence of welding cracks during TIG welding, that is, realizes excellent hot crack resistance, and allows for easy production of a weld joint having high strength and excellent cryogenic impact toughness.

Abstract: A closed battery which is capable of rapidly releasing the internal pressure there while simultaneously disconnecting the current to prevent the internal temperature of the battery from rising and causing the battery to explode. Thus, when the internal pressure of the closed battery is elevated due to a short circuit, overcharge, reverse charge, or the like, internal gas in the battery can be safely discharged and the battery prevented from bursting.

Abstract: The object of the present invention is to provide an explosion-proof safety valve assemblage having a lead cap which allows some of the manufacturing man-hour in the process such as precision working and positioning to be deleted, since the lead cap is integrally formed with an explosion-proof safety valve and serves to provide a current circuit in a battery in place of a conventional one composed of lead plate or lead wire which requires such precision working and positioning operations, and to provide a closed secondary battery using the above mentioned safety valve assemblage.

Abstract: The object of the present invention is to provide a closed battery capable of rapidly releasing the internal pressure thereof and at the same time disconnecting the current to effectively prevent a rise in temperature and explosion so that it may assure the safety and reliability of the battery, when, the internal pressure is elevated due to short circuit, overcharge, reverse charge, or the like in such a completely closed battery. A closed battery of the present invention is provided with a closing member serving as a valve chip, which is composed of a metal substrate 1 in which a valve element 5 is provided and defined by a break line 3, and a metal foil 2 adhered to the inner surface of the metal substrate 1.

Abstract: The object of the present invention is to provide a closed battery capable of rapidly releasing the internal pressure thereof and at the same time disconnecting the current to effectively prevent itself from temperature rising and exploding so that in such a completely closed battery it may assure the safety and reliability thereof, when the internal pressure is elevated due to short circuit, overcharge, reverse charge, or the like. A valve element 5 is provided with a slit 3 between the circumference thereof and a metal substrate 1. When the internal pressure of a battery is elevated, the valve element 5 is smoothly raised up together with a metal foil 2 from a bending fulcrum portion 4 to thereby cut a lead wire 6 or permit a braze portion 8 to detach from the lead wire 6, thus disconnecting the current reliably.

Abstract: A closed battery which is capable of rapidly releasing the internal pressure there while simultaneously disconnecting the current to prevent the internal temperature of the battery from rising and causing the battery to explode. Thus, when the internal pressure of the closed battery is elevated due to a short circuit, overcharge, reverse charge, or the like, internal gas in the battery can be safely discharged and the battery prevented from bursting.

Abstract: The object of the present invention is to provide a closed battery capable of rapidly releasing the internal pressure thereof and at the same time disconnecting the current to effectively prevent itself from temperature rising and explosion so that it may assure the safety and reliability thereof, when the internal pressure is elevated due to short circuit, overcharge, reverse charge, or the like in such a completely closed battery. The formation of a valve element 5 whose center is eccentric to the center of a metal substrate 1 produces a slit 3 having a large width portion around the circumference of a valve element 5. When the internal pressure of a battery is elevated, the valve element 5 is smoothly raised up together with a metal foil 2 from the bending fulcrum portion 4 to thereby cut a lead wire 6 or permit a braze portion 8 to detach from the lead wire 6, thus reliably disconnecting the current.

Abstract: A safety valve element for battery use which ruptures at a stable pressure range so as to release the inner pressure of the battery is disclosed. The safety valve element for battery use comprises a metal substrate which is provided with a perforated opening and a metal foil laminated on the metal substrate so as to close the perforated opening. A battery which is provided with such a safety valve is also disclosed. A battery case provided with such a safety valve is also disclosed. The battery and the battery case lid is produced by forming the perforated opening in the metal substrate, pressure welding the metal foil to the metal substrate and molding the clad material into a form of the battery case lid.