A module for forming battery packs comprising: • a first plate and a second plate arranged parallel to one another and showing four edges also arranged parallel to one another, wherein each of the plates (1, 2) is square- or rectangular-shaped and comprises: ∘ a first edge (1.1, 2.1), ∘ a second edge (1.2, 2.2) adjacent to the first edge (1.1, 2.1) and arranged to its right, ∘ a third edge (1.3, 2.3) arranged opposite the first edge (1.1, 2.1); and ∘ a fourth edge (1.4, 2.4) adjacent to the first edge (1.1, 2.1) and arranged to its left, wherein the third edge (1.3, 2.3) is adjacent to the second edge (1.2, 2.2) and is also adjacent to the fourth edge (1.4, 2.4), wherein the first, second, third and fourth edges (1.1, 1.2, 1.3, 1.4) of the first plate further correspond with the first, second, third and fourth edges (2.1, 2.2, 2.3, 2.4) of the second plate, • an even number of rod-shaped cells with a positive terminal (+) at one end and a negative terminal (-) at the opposite end, all arranged parallel to one another and placed between the first plate and the second plate, and linked to them through the terminals, • a set of electrical connections in the first plate between the terminals of cells attached to said first plate and a set of connections in the second plate between terminals of cells attached to said second plate such that they establish a series connection of the cells, • a first electrical connection terminal (1.1.1) centrally arranged in the first edge (1.1) of the first plate and a second electrical connection terminal (1.2.1) centrally arranged in the second edge (1.2) of the first plate, wherein both electrical connection terminals (1.1.1, 1.2.1) are electrically communicated with a terminal (+, -) of the end cell of the series connection; and • a third electrical connection terminal (1.3.1) centrally arranged in the third edge (1.3) of the first plate and a fourth electrical connection terminal (1.4.1) centrally arranged in the fourth edge (1.4) of the first plate, wherein both electrical connection terminals (1.3.1, 1.4.1) are electrically communicated with the terminal (+, -) of the opposite cell of the end of the series connection; and • wherein the first, second, third and fourth electrical connection terminals (1.1.1, 1.2.1, 1.3.1, 1.4.1) of the first plate are suitable for being connected with the terminals of an edge (1.1, 1.2, 1.3, 1.4) of the first plate of another module also arranged parallel and adjacent thereto. • a first plate and a second plate arranged parallel to one another and showing four edges also arranged parallel to one another, wherein each of the plates (1, 2) is square- or rectangular-shaped and comprises: ∘ a first edge (1.1, 2.1), ∘ a second edge (1.2, 2.2) adjacent to the first edge (1.1, 2.1) and arranged to its right, ∘ a third edge (1.3, 2.3) arranged opposite the first edge (1.1, 2.1); and ∘ a fourth edge (1.4, 2.4) adjacent to the first edge (1.1, 2.1) and arranged to its left, wherein the third edge (1.3, 2.3) is adjacent to the second edge (1.2, 2.2) and is also adjacent to the fourth edge (1.4, 2.4), wherein the first, second, third and fourth edges (1.1, 1.2, 1.3, 1.4) of the first plate further correspond with the first, second, third and fourth edges (2.1, 2.2, 2.3, 2.4) of the second plate, ∘ a first edge (1.1, 2.1), ∘ a second edge (1.2, 2.2) adjacent to the first edge (1.1, 2.1) and arranged to its right, ∘ a third edge (1.3, 2.3) arranged opposite the first edge (1.1, 2.1); and ∘ a fourth edge (1.4, 2.4) adjacent to the first edge (1.1, 2.1) and arranged to its left, wherein the third edge (1.3, 2.3) is adjacent to the second edge (1.2, 2.2) and is also adjacent to the fourth edge (1.4, 2.4), wherein the first, second, third and fourth edges (1.1, 1.2, 1.3, 1.4) of the first plate further correspond with the first, second, third and fourth edges (2.1, 2.2, 2.3, 2.4) of the second plate, • an even number of rod-shaped cells with a positive terminal (+) at one end and a negative terminal (-) at the opposite end, all arranged parallel to one another and placed between the first plate and the second plate, and linked to them through the terminals, • a set of electrical connections in the first plate between the terminals of cells attached to said first plate and a set of connections in the second plate between terminals of cells attached to said second plate such that they establish a series connection of the cells, • a first electrical connection terminal (1.1.1) centrally arranged in the first edge (1.1) of the first plate and a second electrical connection terminal (1.2.1) centrally arranged in the second edge (1.2) of the first plate, wherein both electrical connection terminals (1.1.1, 1.2.1) are electrically communicated with a terminal (+, -) of the end cell of the series connection; and • a third electrical connection terminal (1.3.1) centrally arranged in the third edge (1.3) of the first plate and a fourth electrical connection terminal (1.4.1) centrally arranged in the fourth edge (1.4) of the first plate, wherein both electrical connection terminals (1.3.1, 1.4.1) are electrically communicated with the terminal (+, -) of the opposite cell of the end of the series connection; and • wherein the first, second, third and fourth electrical connection terminals (1.1.1, 1.2.1, 1.3.1, 1.4.1) of the first plate are suitable for being connected with the terminals of an edge (1.1, 1.2, 1.3, 1.4) of the first plate of another module also arranged parallel and adjacent thereto.