A foldable flexible assembling of cells for a lithium-ion battery comprising: - a separator formed by a central band containing an electrolyte and defining, when in flat configuration, a longitudinal direction (X, X') between a first end and a second end, - a series of n negative electrodes located on the first side of the separator and which are disposed along said longitudinal direction, each negative electrode of a pair of adjacent electrodes being physically separated from the other negative electrode of said pair of adjacent electrodes along a negative electrode separation line orthogonal to said longitudinal direction, with n being an integer equal to or larger than two, - a series of n positive electrodes located on the second side of the separator and which are disposed in a longitudinal direction, each positive electrode of a pair of adjacent electrodes being physically separated from the other positive electrode of said pair of adjacent electrodes along a positive electrode separation line orthogonal to said longitudinal direction, * wherein each negative electrode corresponds to an opposite positive electrode, * wherein a portion of said separator, each negative electrode located on the first side of the separator and the corresponding positive electrode located on the second side of the separator form an individual cell (40a, 40b, 40c), * wherein each of said positive electrode separation line corresponds to an opposite negative electrode separation line, each said positive electrode separation line forming with said corresponding opposite negative electrode separation line a folding zone between two adjacent individual cell (40a, 40b, 40c)s, - a first current collector comprising a layer covering continuously said series of negative electrodes so as to ensure electrical connection between all said negative electrodes - a second current collector comprising a layer covering continuously said series of positive electrodes so as to ensure electrical connection between all said positive electrodes. - a separator formed by a central band containing an electrolyte and defining, when in flat configuration, a longitudinal direction (X, X') between a first end and a second end, - a series of n negative electrodes located on the first side of the separator and which are disposed along said longitudinal direction, each negative electrode of a pair of adjacent electrodes being physically separated from the other negative electrode of said pair of adjacent electrodes along a negative electrode separation line orthogonal to said longitudinal direction, with n being an integer equal to or larger than two, - a series of n positive electrodes located on the second side of the separator and which are disposed in a longitudinal direction, each positive electrode of a pair of adjacent electrodes being physically separated from the other positive electrode of said pair of adjacent electrodes along a positive electrode separation line orthogonal to said longitudinal direction, * wherein each negative electrode corresponds to an opposite positive electrode, * wherein a portion of said separator, each negative electrode located on the first side of the separator and the corresponding positive electrode located on the second side of the separator form an individual cell (40a, 40b, 40c), * wherein each of said positive electrode separation line corresponds to an opposite negative electrode separation line, each said positive electrode separation line forming with said corresponding opposite negative electrode separation line a folding zone between two adjacent individual cell (40a, 40b, 40c)s, * wherein each negative electrode corresponds to an opposite positive electrode, * wherein a portion of said separator, each negative electrode located on the first side of the separator and the corresponding positive electrode located on the second side of the separator form an individual cell (40a, 40b, 40c), * wherein each of said positive electrode separation line corresponds to an opposite negative electrode separation line, each said positive electrode separation line forming with said corresponding opposite negative electrode separation line a folding zone between two adjacent individual cell (40a, 40b, 40c)s, - a first current collector comprising a layer covering continuously said series of negative electrodes so as to ensure electrical connection between all said negative electrodes - a second current collector comprising a layer covering continuously said series of positive electrodes so as to ensure electrical connection between all said positive electrodes.