NOVELTY - Battery manufacture involves forming non-formed active material on each electrode (9). The electrodes and initially non-formed active material are held under a mechanical pressure during the formation step to limit the volume change of the active material during this step. The electrodes, after the formation step, are assembled to complete a battery. The mechanical pressure of 50-250 (preferably 100-200) kPa is applied so that active material is formed within constant volume.    USE - For manufacturing battery, e.g. bipolar battery.    ADVANTAGE - The method is capable of controlling the active materials during formation so that undesired volume changes are limited, thus undesired surface irregularities of the electrodes are avoided, which could otherwise be problematic with different types of batteries. It avoids structural transformations that the active materials undergo during formation that bring about the volume changes that could result in undesired surface irregularities of the electrodes. The risk of volume changes tending to break off the active materials from the plane intermediate wall of the electrode is avoided or reduced. The bipolar electrodes are assembled to batteries without rinsing and drying and the occurrence of high heat development in the battery is avoided.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) device for the manufacture of a battery with electrodes formed active material, comprising a holder for receiving non-formed electrodes, and mechanism for, during a formation step, holding the electrodes; and    (2) battery including electrolyte and electrodes with active material, in which electrodes in assembly exhibiting limited volume changes in the active material as a result of having been held under a mechanical pressure which limits volume changes inside a holder during a formation step.    Formation is carried out on a pile of a number of bipolar electrodes, for forming on each electrode positive and negative active material on either side of an electron conductive wall.    DESCRIPTION OF DRAWING(S) - The figure shows a cassette for pressurizing a battery pile.    Current collectors (7, 8)    Electrode (9)    pressurizing element (12)    Cassette (16)