Pressure equalising device

1. A pressure compensation device for compensating an internal pressure in a housing of an electrochemical device, comprising:

at least one gas-permeable membrane configured for gas exchange between an interior of the housing and surroundings of the electrochemical device;

a valve body configured to be transferred from a home position resting on a valve seat into a use position remote from the valve seat, the valve body comprising a gas throughflow opening that is sealed by the gas-permeable membrane; and

a pressure generating mechanism configured to counteract the internal pressure and to hold the valve body in the home position, provided that the internal limiting pressure is not exceeded, the pressure generative mechanism further configured such that, when the internal limiting pressure is exceeded, the pressure generating mechanism releases the valve body such that it can move to the use position,

wherein when the valve body is in the use position, the pressure generating mechanism is remote from and does not act on the valve body.

2. The pressure compensation device according to claim 1 , wherein the valve body comprises a valve surface to which the internal pressure is applied, and

wherein the valve surface is formed by a surface of the gas-permeable membrane at least in part.

3. The pressure compensation device according to claim 2 , wherein the valve surface is entirely or substantially entirely formed by the gas-permeable membrane.

4. The pressure compensation device according to claim 1 , wherein the gas-permeable membrane extends in a membrane plane which extends at an angle to a movement axis of the valve body.

5. The pressure compensation device according to claim 4 , wherein the gas-permeable membrane and the movement axis are arranged concentrically relative to one another.

6. The pressure compensation device according to claim 4 , wherein the membrane plane extends perpendicularly to the movement axis.

7. The pressure compensation device according to claim 1 , wherein the pressure generating mechanism comprises at least one spring arm.

8. The pressure compensation device according to claim 7 ,

wherein the valve body comprises at least one stop element at a periphery of the valve body, the stop element comprising a stop surface,

wherein the spring arm is configured such that, when in the home position, an end portion of the spring arm contacts the stop surface to hold the valve body in the home position, and

wherein the spring arm is configured such that, when the internal limiting pressure is exceeded, the spring arm is first deflected radially outward allowing the valve body to move to the use position, and then springs back radially inwards.

9. The pressure compensation device according to claim 7 , wherein the at least one spring arm comprises a plurality of spring arms spaced apart from each other in the radial direction.

10. The pressure compensation device according to claim 1 , further comprising a housing insert configured to be fastened on or in an opening of the housing of the electrochemical device.

11. The pressure compensation device according claim 10 , wherein the housing insert comprises an interior for arranging the valve body and the gas-permeable membrane that is connected to the valve body.

12. The pressure compensation device according to claim 1 , wherein, when the valve body is in the home position, gas is guided along a gas-exchange path,

wherein, when the valve body is in the use position, gas is guided along a flow path which differs from the gas exchange path.

13. The pressure compensation device according to claim 12 , wherein the flow path extends around the valve body.

14. The pressure compensation device according to claim 1 , wherein, when in the use position, the valve body is configured to be pressed back into the home position where the valve body is held in place by the pressure generating mechanism.