METAL AIR BATTERY

To prevent leakage of an electrolyte by enhancing adhesiveness between an exterior member and a water-repellent film of a metal air battery.SOLUTION: In a metal air battery 10 that comprises a battery case 13, an air electrode 15 and a metal negative electrode 16, a first resin film 11 configuring the battery case 13 is provided with an air in-take port 111. A water-repellent film 14 is welded to the air in-take port 111. At least one of the water-repellent film 14 and the first resin film 11 is welded while being configured to have a surface roughness larger than a rear face roughness in a welded region where both films are overlapped with each other.SELECTED DRAWING: Figure 2 【課題】金属空気電池の外装部材と撥水膜との接着性を高めて電解液の漏出を防止する。【解決手段】電池ケース１３、空気極１５および金属負極１６を備える金属空気電池１０において、電池ケース１３を構成する第１樹脂フィルム１１には空気取込口１１１が設けられ、この空気取込口１１１に撥水膜１４が溶着されている。撥水膜１４および第１樹脂フィルム１１の少なくとも一方は、両者が重なり合う溶着領域で、表面粗さが裏面粗さよりも大きく構成されて溶着されてなる。【選択図】図２