Battery pack, secondary battery housing case, and battery pack assembling method

A box-shaped secondary battery storage case, comprising:

• a lower case;
• and
• an upper case joined to the lower case, wherein
• the lower case includes a bottom plate, and a surrounding side wall standing around the bottom plate so as to be directed upward, and including left, right, front, and back side walls,
• the upper case includes a top, and a surrounding side wall standing around the top so as to be directed downward, and including left, right, and back side walls,
• an upper portion of the front side wall of the lower case includes a flat roof sheet portion protruding backward in a direction parallel to the bottom plate,
• a front portion of the top of the upper case includes a flat roof insertion piece that is inserted into the roof sheet portion so as to be in contact with the roof sheet portion and protrudes frontward in a direction parallel to the top,
• at least one of an upper insertion piece of the back side wall of the upper case or a lower insertion piece of the back side wall of the lower case is provided, where the upper insertion piece is inserted into the lower case so as to be in contact with the back side wall of the lower case, and the lower insertion piece is inserted into the upper case so as to be in contact with the back side wall of the upper case, and
• a space surrounded by the top and surrounding side wall of the upper case and the bottom plate and surrounding side wall of the lower case is formed as a space for housing the secondary battery by inserting the roof insertion piece of the upper case into the lower case such that the roof insertion piece is in contact with the roof sheet portion of the lower case, and at least either inserting the upper insertion piece into the lower case such that the upper insertion piece is in contact with the back side wall of the lower case, or inserting the lower insertion piece into the upper case such that the lower insertion piece is in contact with the back side wall of the upper case.

A method for assembling a battery pack while housing a secondary battery in a box-shaped secondary battery storage case including a lower case and an upper case joined to the lower case, where the lower case includes a bottom plate, a surrounding side wall standing around the bottom plate so as to be directed upward, and including left, right, front, and back side walls, a flat roof sheet portion provided on an upper portion of the front side wall to protrude backward in a direction parallel to the bottom plate, and a lower insertion piece provided on the back side wall, and the upper case includes a top, a surrounding side wall standing around the top so as to be directed downward, and including left, right, and back side walls, a flat roof insertion piece provided on a front portion of the top, inserted into the roof sheet portion so as to be in contact with the roof sheet portion and protruding frontward in a direction parallel to the top, and an upper insertion piece provided on the back side wall, the method comprising steps of:

• placing the secondary battery on the bottom plate of the lower case;
• obliquely inserting the upper case into the lower case including the bottom plate on which the secondary battery has been placed, such that the roof insertion piece of the upper case is inserted into the lower case so as to be in contact with the roof sheet portion of the lower case;
• and
• bringing the back side wall of the upper case closer to the back side wall of the lower case, and housing the secondary battery in the secondary battery storage case at least either by inserting the upper insertion piece into the lower case such that the upper insertion piece is in contact with the back side wall of the lower case, or by inserting the lower insertion piece into the upper case such that the lower insertion piece is in contact with the back side wall of the upper case.