The invention relates to the technical field of
fuel cells, and provides a preparation method of a
metal bipolar plate of a
proton exchange membrane fuel
cell. According to the invention, the
metal bipolar plate is prepared by adopting a method of firstly
coating, then
welding and finally
hydroforming, so that the uniform thickness of the
coating can be ensured, and the consistency of
corrosion resistance and
contact resistance of each part of the bipolar plate is ensured; and when the two
layers of
metal plates are welded, one non-
welding area is reserved on each of the two sides, during hydraulic forming, the non-
welding areas serve as
liquid injection holes to inject high-pressure liquid between the two
layers of metal plates, under the action of
hydraulic pressure, the upper layer of metal plate is attached to the
cavity wall of an upper mold plate, and the lower layer of metal plate is attached to the
cavity wall of a lower mold plate, so a
cathode plate and an
anode plate are formed at the same time. When the method is adopted for hydraulic forming, the
coating cannot be damaged, the formed runner is high in precision, the product percent of pass is high, and simultaneous forming of the
cathode plate and the
anode plate is achieved for the first time.