Explosion-proof venting valve device

An explosion-proof venting valve for a battery pack, the explosion-proof venting valve comprising:

• a protective cover;
• a cover seat engaged with the protective cover;
• a membrane being water-impermeable and gas-permeable, the membrane being disposed under the protective cover;
• a valve body configured to be connected with a housing of the battery pack;
• a self-locking mechanism disposed on the cover seat, the protective cover, the cover seat, the membrane and the self-locking mechanism forming a cover assembly defining a venting passage;
• and
• a filter element housed in the valve body, the filter element and the valve body defining a valve passage,
• wherein the self-locking mechanism is configured to:
• engage with a corresponding locking structure on the valve body, so that the cover assembly is fixed relative to the valve body and gas exchange between an interior of the battery pack and an environment via both the valve passage and the venting passage is allowed, when a pressure of the interior of the battery pack is equal to or less than an environment pressure or when the pressure of the interior of the battery pack is greater than the environment pressure but a pressure difference between the interior of the battery pack and the environment pressure is less than a predetermined threshold;
• and
• disengage with the corresponding locking structure on the valve body, so that the cover assembly is released from the valve body and pressure relief via the valve passage only without being through the venting passage is allowed, when the pressure of the interior of the battery pack is greater than the environment pressure and the pressure difference between the interior of the battery pack and the environment pressure is greater than the predetermined threshold, and
• the self-locking mechanism comprises a biasing spring and a ball locking assembly, the ball locking assembly comprising:
• a hollow cylindrical body member defining a locking mechanism central venting passage, the membrane being disposed on a top surface of the hollow cylindrical body member;
• a supporting flange extending circumferentially around outside of the hollow cylindrical body member, the supporting flange supporting the biasing spring;
• and
• a plurality of ball seat chambers distributed circumferentially around the hollow cylindrical body member, each of the plurality of ball seat chambers being in fluid communication with the locking mechanism central venting passage and being configured to house a locking ball,
• the cover seat comprises a conical portion at a lower portion thereof, and at least one through-hole extending through a side wall of the cover seat and being in fluid communication with the plurality of ball seat chambers, and
• the valve body comprises a protrusion extending upwards from a center of the valve body, the protrusion comprising an arc-shaped groove extending circumferentially around the protrusion or a plurality of partial spherical recesses circumferentially aligned with the plurality of ball seat chambers, to engage with the locking ball.