NOVELTY - The method involves placing a stack (48) of electrodes (24, 28) inside a battery compartment (40), and placing an elastic material, which is compressed in a compression bag (440), between walls (3, 6) of the compartment and the stack. An opening is formed in the bag, such that the material that was initially compressed in the bag expands and exerts a compressive force on the stack to rest on the walls of the compartment. A wedge (12) is placed between the bag and the walls or between the bag and the stack.    USE - Used for compressing a stack of electrodes in a compression bag of a storage battery (claimed) in the motor vehicle field for improving cycle endurance of the battery.    ADVANTAGE - The opening is formed in the bag, so that the material that was initially compressed in the bag expands and exerts the compressive force on the stack to rest on the walls of the compartment to open or damage the bag, thus ensuring better output and cycle endurance of the battery. The bag remains standard and does not require any adaptation except a reinforcement for its thickness or addition of an external system for maintaining its sides. The method allows obtaining constant elastic force, and allows variation of volume of the electrode stack to limit a creep and ensure better output of the battery. The placement of the wedge improves the wedging or pre-compression of the stack of electrodes, and avoids deformation of a non-reinforced bag.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a storage battery    (2) a compression bag for compression of a stack of electrodes.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic of a battery including a compression bag.    Battery compartment`s longitudinal external and internal walls (3, 6)    Battery compartment`s transverse internal wall (7)    Electrode stack`s longitudinal sides (10, 11)    Wedge (12)    Electrodes (24, 28)    Battery compartment (40)    Electrode stack (48)    Compression bag (440)