A rechargeable electrochemical cell is provided having a
pressure-responsive apparatus for determining a charge termination point.
In particular, a reversible pressure-responsive switch may be disposed in
a cap at the open end of a rechargeable metal hydride cell. The
reversible pressure-responsive switch may also contain a vent system for
releasing the cell internal pressure. Alternatively, a rechargeable cell
may include a strain gauge disposed in its outer surface whose resistance
changes as the outer surface of the battery expands due to internal
pressure accumulation during charging. Additionally, a rechargeable cell
is used combination with a charging source that can supply constant
voltage, constant current, alternating current, or voltage that varies
between a minimum threshold and a maximum threshold.