| abstract |
A hybrid energy storage device has at least one lead-based positive electrode and at least one carbon-based negative electrode, a separator between the electrodes, a casing which will contain the electrodes and separator, and an acid electrolyte. The separator is gas permeable, and is capable of absorbing and entraining acid electrolyte. The separator has a finite capacity for absorption of acid electrolyte, and the quantity of acid electrolyte which is present in the cell is less than the finite capacity of the separator. Upon assembly of the cell, the casing is sealed, and there is no liquid acid electrolyte within the assembled cell. |