Abstract: The invention is to provide a bipolar plate having keys on at least two sides thereof, with such keys have piercing holes thereon; a bipolar plate, a membrane electrode assembly (“MEA”) and a gasket are formed as a unit in the Bipolar Plate Assembly (“BPA”), and provided any of the MEA in a BPA is damaged and needs to be replaced, keys added on other BPAs enable screw rods to fasten sectionally, thus the BPA containing the damaged MEA can be separated, such that the damaged MEA can be dissembled and replaced. The invention further provides a PEM fuel cell, which comprises a plurality of BPAs, with each of such BPA having a number of bipolar plates having keys, MEAs and gaskets. Moreover, the invention further provides a method for replacing MEAs in a PEM fuel cell, whereby damaged MEAs in a PEM fuel cell can be expediently and safely dissembled, repaired or replaced, and the procedure for re-assembling a PEM fuel cell is thus simplified.

Abstract: The invention provides a separator in lead acid battery, composed of fiber material and polymers; the polymers provide functions of increasing the mechanical strength for separators, avoiding shortage between positive and negative electrodes, and decreasing the thickness of separators. The invention also provides a manufacturing method of battery separators, whereby polymers are used to coat or absorb to porous separators through means of spraying, immersing, brushing, adhering or other similar means, thus acquiring thinner battery separators with increased mechanical strength.