Disclosed is a hollow molded article which has an opening portion communicating with a flow channel and which can be manufactured simply. The hollow molded article includes a panel and flow channels. The panel includes a first resin sheet and a second resin sheet partly welded with the first resin sheet. The flow channels are disposed between the first resin sheet and the second resin sheet, and include connection portions for external connection which are disposed on a peripheral edge of the panel. The connection portions are formed by the first resin sheet and the second resin sheet.

A method for manufacturing a plastic fuel tank including: a) inserting a plastic parison including two distinct parts into an open two-cavity mold; b) inserting a core, bearing at least part of a reinforcing element configured to create a link between the two parison parts, inside the parison; c) pressing the parison firmly against the mold cavities, for example by blowing through the core and/or creating suction behind the cavities; d) fixing the part of the reinforcing element to at least one of the parison parts using the core; e) withdrawing the core; f) closing the mold, bringing its two cavities together to grip the two parison parts around their periphery to weld them together; g) injecting a pressurized fluid into the mold and/or creating a vacuum behind the mold cavities to press the parison firmly against the mold cavities; and h) opening the mold and extracting the tank.

A blow molded article of manufacture includes first and second battery enclosures each having respective first and second laterally outward extending flanges, and a parison made of a polymeric material. The first and second battery enclosure components are disposed facing each other and with their respective first and second laterally outward extending flanges registered with each other and spaced apart from each other by an offset. The parison is sandwiched between and connects together the first and second battery enclosure components, such that the parison conforms with interior surfaces of the battery enclosure components and with the parison substantially filling the offset. The article of manufacture may be cut along a cut line through the parison and within the offset around an outer perimeter of the article of manufacture, thereby separating the article of manufacture into first and second battery enclosure assemblies. Methods of formation are also disclosed.