Battery pack including valve structure having valve member biased toward inner surface of pack case by biasing member

A battery pack comprising:

• a battery cell;
• a pack case that accommodates the battery cell and that is provided with an opening;
• and
• a valve structure provided to open and close the opening, wherein
• the valve structure includes a valve member having:
• a valve body portion fitted to an inner peripheral surface of the opening,
• a stem portion protruding from the valve body portion toward an inner side of the pack case,
• an adjustment screw, wherein the adjustment screw is screwed to a tip of the stem portion, and
• a biasing member provided inside the pack case, wherein a biasing force of the biasing member is adjustable by rotating the adjustment screw, the biasing member biases the valve member toward the inner side of the pack case using the biasing force when a clearance exists between an outer peripheral surface of the valve body portion and the inner peripheral surface of the opening, and
• when an internal pressure of the pack case is increased:
• the valve member is moved to an outer side of the pack case so as to form the clearance between the outer peripheral surface of the valve body portion and the inner peripheral surface of the opening, and
• the biasing member biases the valve member toward an inner side of the pack case.