A battery module casing (2, 15, 19) configured to house at least one battery cell, said battery module casing (2, 15, 19) comprising - a first metal plate, configured to form a positive terminal of a battery module and to be positioned on a first side of said at least one battery cell, - a second metal plate, configured to form a negative terminal of a battery module and to be positioned on an opposite second side of said at least one battery cell, - a lateral wall element configured to extend around a lateral periphery of said at least one battery cell, wherein the lateral wall element is located between said first metal plate and said second metal plate, and wherein said lateral wall element comprises an electrically isolating material and is sealingly attached to the first metal plate and to the second metal plate respectively, wherein at least one of said first and second metal plates (4, 5) comprises at least one lateral extension (7, 8) that, along at least a part of a periphery of the plate to which it is associated, forms a lateral wall together with said lateral wall element, said battery module being characterised in that the casing is subdivided in two halves (2', 2") that are interconnected along a partition line, wherein a first one of said halves comprises the first metal plate and a first part of said lateral wall element and the second one (2") of said halves comprises the second metal plate and a second part (6") of said lateral wall element, and in that the first part of the lateral wall element is a polymer moulded onto and enclosing the at least one lateral extension of the first metal plate, and that the second part (6") of the lateral wall element is a polymer moulded onto and enclosing the at least one lateral extension of the second metal plate. - a first metal plate, configured to form a positive terminal of a battery module and to be positioned on a first side of said at least one battery cell, - a second metal plate, configured to form a negative terminal of a battery module and to be positioned on an opposite second side of said at least one battery cell, - a lateral wall element configured to extend around a lateral periphery of said at least one battery cell, wherein the lateral wall element is located between said first metal plate and said second metal plate, and wherein said lateral wall element comprises an electrically isolating material and is sealingly attached to the first metal plate and to the second metal plate respectively, wherein at least one of said first and second metal plates (4, 5) comprises at least one lateral extension (7, 8) that, along at least a part of a periphery of the plate to which it is associated, forms a lateral wall together with said lateral wall element, said battery module being characterised in that the casing is subdivided in two halves (2', 2") that are interconnected along a partition line, wherein a first one of said halves comprises the first metal plate and a first part of said lateral wall element and the second one (2") of said halves comprises the second metal plate and a second part (6") of said lateral wall element, and in that the first part of the lateral wall element is a polymer moulded onto and enclosing the at least one lateral extension of the first metal plate, and that the second part (6") of the lateral wall element is a polymer moulded onto and enclosing the at least one lateral extension of the second metal plate.