Bus bar module and battery pack

A battery pack comprising:

• a battery module formed of a plurality of battery cells;
• and
• a bus bar module that electrically connects the battery cells in series or in parallel, wherein
• the bus bar module includes:
• a plurality of bus bars each having a through hole into which an electrode terminal of an electrode terminal group is inserted, the electrode terminal group including a plurality of electrode terminals which are arranged linearly in an arranging direction on the battery module, the plurality of bus bars being arranged along the arranging direction of the plurality of electrode terminals in the electrode terminal group, and
• a flat cable including a plurality of conductor parts which are respectively and electrically connected to the plurality of bus bars, and an insulating holding part configured to hold the plurality of bus bars, wherein
• each of the plurality of bus bars includes a holding body configured to be fitted to the flat cable,
• the holding part includes holding holes corresponding to the plurality of bus bars, the holding holes including at least one first holding hole and at least one second holding hole, the at least one first holding hole having a portion of a reference holding body of a reference bus bar of the plurality of bus bars inserted therein, and being configured to restrict a relative movement of the reference bus bar with respect to the flat cable at least in the arranging direction by restricting a relative movement of the reference holding body in the arranging direction, the at least one second holding hole having a portion of another holding body of another bus bar of the plurality of bus bars inserted therein, and being configured to allow a relative movement of the another bus bar with respect to the flat cable in the arranging direction, by allowing a relative movement of the another holding body in the arranging direction,
• wherein the second holding holes have a length that is longer than a length of the first holding holes in the arranging direction.