Bipolar plate with insertable diaphragm and fuel cell stack

A bipolar plate for a fuel cell, comprising:

• an active region;
• an edge region surrounding the active region, the edge region being associated to a first media guide fluidically connected to a first passage and a second media guide fluidically connected to a second passage;
• a media duct which runs through the active region and fluidically connects the first passage to the second passage,
• wherein at least one of the first and second media guides comprises a first partial chamber and a second partial chamber having the first passage or the second passage, respectively,
• wherein a media guide channel is provided between the first partial chamber and the second partial chamber,
• wherein a flow cross-section of the media guide is reduced at the media guide channel provided between the first partial chamber and the second partial chamber such that a flow cross-section of the media guide channel is smaller than a flow cross-section of the first partial chamber adjacent to the media guide channel and smaller than a flow cross-section of the second partial chamber adjacent to the media guide channel, and
• wherein the second partial chamber is configured to receive a diaphragm or the diaphragm is inserted into the second partial chamber.