A method of manufacturing a high-pressure fluid vessel includes forming a first portion of a high-pressure fluid vessel with a molding process. The high-pressure fluid vessel includes a stack of capsules. Each capsule includes a first domed end, a second domed end, and a semicylindrical portion extending between and connecting the first domed end to the second domed end. The method further includes forming a second portion of a high-pressure fluid vessel with the molding process. The second portion of the high-pressure fluid vessel is positioned adjacent to the first portion of the high-pressure fluid vessel. The second portion of the high-pressure fluid vessel is welded to the first portion of the high-pressure fluid vessel.