Bipolar plate for a fuel cell stack or an electrolyzer stack

A bipolar plate for a fuel cell stack or for an electrolyzer stack, comprising:

• an anode plate and a cathode plate which are joined to face-to-face,
• wherein the face of the anode plate that faces the face of the cathode plate delimits an internal space that forms a circuit for the distribution of a first fluid, thereby forming a bipolar plate,
• the anode plate comprising a first opening,
• the cathode plate comprising a second opening,
• wherein the first opening and the second opening facing one another thereby forming a collector configured to enable the passage of the first fluid or a second fluid through the bipolar plate,
• wherein the bipolar plate comprises a plane,
• wherein the first opening has a peripheral end and the second opening has a peripheral end,
• wherein the first opening and the second opening have distinct dimensions such that at least part of the peripheral end of the first opening and at least part of the peripheral end of the second opening are offset in relation to one another in the plane of the bipolar plate, forming a shoulder at the peripheral end of the collector.