Humidifier

A humidifier for a fuel cell system for a vehicle with a fuel cell for humidifying a dry air flowing to the fuel cell with a humid air flowing from the fuel cell, comprising:

• a membrane stack including a plurality of flat membranes stacked in the membrane stack at a distance from one another in a stacking direction;
• the membrane stack has having two opposite lateral faces aligned parallel to the stacking direction for an inflow and an outflow of the dry air into and out of the membrane stack;
• the membrane stack further having two further opposing lateral faces aligned parallel to the stacking direction for an inflow and an outflow of the humid air into and out of the membrane stack;
• the membrane stack has further having two airtight end faces aligned transversely to the stacking direction;
• a housing in which the membrane stack is accommodated;
• and
• two circumferential seals clamped between the membrane stack and the housing in an airtight manner;
• wherein the two seals are assigned to the two further lateral faces for the humid air and separate the two further lateral faces for the humid air within the housing from one another and from the two lateral faces for the dry air and from the two end faces in an airtight manner.