Battery pack and stacking method thereof

The present invention provides a battery pack and a stacking method thereof. According to the battery pack, each battery of the battery pack comprises a positive electrode lug and a negative electrode lug on both sides in a width direction, the positive electrode lug of each battery is positioned at spaced first position or second position on the left side while the negative electrode lug of each battery is positioned at spaced first position or second position on the right side, or the positive electrode lug of each battery is positioned at spaced first position or second position on the right side while the negative electrode lug of each battery is positioned at spaced first position or second position on the left side, the positive electrode lugs and the negative electrode lugs of the sequentially-stacked and adjacent batteries are correspondingly connected in series to form electrode lug pairs, the positive electrode lug and the negative electrode lug in the electrode pair are positioned at one of the first position on the same left side, the second position on the same left side, the first position on the same right side and the second position on the same right side, and the one electrode lug pair positioned at the same side in the width direction and the positive electrode lug or negative electrode lug positioned at the corresponding side and of the battery adjacent to the two batteries stacked on the one electrode lug are spaced during the series connection.