| 摘要 |
PURPOSE:To lengthen the temperature holding time of a stack and to remarkably improve the discharge life of a battery by using a battery case obtained by sealing a double battery case under reduced pressure below a specified value. CONSTITUTION:A double battery case having a space between an inner battery case 1 and an outer battery case 2 is used. Both battery cases 1, 2 are joined by welding or silver soldering, and the space 9 is sealed under a reduced pressure of 1X10<3>Torr or less to form a heat insulating layer. Even if the thickness of the heat insulating layer is thin, the stack temperature inside a battery is held at operating temperature for a long time. If the reduced pressure value is 1X10<2>Torr or more, the outflow of heat is sharply increased, however, if it is 1X10<3>Torr or less, the outflow of heat is remarkably decreased provided the thickness of the heat insulating layer is 1mm or more. The outflow of heat value generated in a battery for operation is retarded, and a thermal battery which is operable for a long time is obtained. |
