Middle or large-sized battery pack of improved safety

摘要

Disclosed herein is a middle or large-sized battery pack including a battery module assembly configured in a structure in which a plurality of battery modules, each of which comprises a plurality of battery cells or unit modules connected in series to each other while being mounted in a module case, is electrically connected to each other while being arranged in a lateral direction such that the battery modules are in contact with each other, a pair of side support members for covering sides of outermost battery modules of the battery module assembly, and at least one top connection member for connecting the side support members at a top of the battery module assembly, wherein at least one of the side support members has a region (weak portion) exhibiting low resistance to volume expansion, the weak portion being partially formed at the at least one of the side support members for inducing local deformation of the battery modules upon occurrence of swelling, thereby causing a short circuit.

主权项

1. A middle or large-sized battery pack comprising:
(a) a battery module assembly having a plurality of battery modules, each battery module comprising a plurality of battery cells or unit modules, wherein the battery modules are fixed such that a stacked state of the battery cells or the unit modules is maintained due to even volume change of the battery cells or the unit modules during charge and discharge of the battery cells or the unit modules, expansion stress of the battery cells due to swelling concentrates on an electrode terminal connection region between the battery cells or the unit modules, and the electrode terminal connection region is configured in a structure having low resistance to volume expansion such that the electrode terminal connection region is ruptured, when the swelling exceeds a predetermined value, thereby causing a short circuit, each of which comprises a plurality of unit modules connected in series to each other while being mounted in a module case, or a plurality of battery cells is electrically connected to each other while being arranged in a lateral direction such that the unit modules or the battery cells are in contact with each other; (b) a pair of side support members for covering sides of outermost battery modules; and (c) at least one top connection member for connecting the side support members to improve coupling strength between the battery modules at a top of the battery module assembly, wherein at least one of the side support members has a weak portion exhibiting low resistance to volume expansion, the weak portion being partially formed at the at least one of the side support members for inducing local physical deformation of the battery modules or the battery cells upon occurrence of swelling, thereby causing a short circuit, wherein the weak portion is formed at a position of the outermost battery module corresponding to a series connection region or a region adjacent thereto, wherein the weak portion comprises a cutout part through which the series connection region is exposed or a notch part having a notch formed at the side support member corresponding to the series connection region, and wherein the series connection region protrudes outside of the side support member through the weak portion.