Battery module

A battery module comprising:

• first through third battery packs different from each other;
• and
• a bus pattern disposed outside the first through third battery packs and electrically connecting the first through third battery packs to one another and comprising i) a main body including a single input/output point of a charging/discharging path and ii) first through third branching portions that branch from the main body and include first through third contact points respectively connected to the first through third battery packs, wherein the single input/output point of the main body is configured to collect discharging currents received from the first through third battery packs and discharge the currents to an external device and distribute charging currents received from the external device to the first through third branching portions,
• wherein, along the bus pattern, a first distance is defined as the distance between the single input/output point and the first contact point, a second distance is defined as the distance between the single input/output point and the second contact point and a third distance is defined as the distance between the single input/output point and the third contact point, wherein the first distance is less than the second distance, and the second distance is less than the third distance, and
• wherein a first current flow width of the first branching portion is less than a second current flow width of the second branching portion, and the second current flow width is less than a third current flow width of the third branching portion,
• wherein each of the first through third battery packs comprises a plurality of battery cells, an input/output terminal for the battery cells, and a case which accommodates the battery cells and exposes the input/output terminal, wherein the first through third contact points of the bus pattern are connected to the input/output terminal of the battery cells, and
• wherein the bus pattern directly connects the single input/output point and each of the first through third contact points connected to the input/output terminal of the first through third battery packs.