A battery module, characterized in comprising: a lower case; a plurality of battery cells sequentially stacked and received in the lower case; and a heat conducting plate, wherein the lower case is connected to the heat conducting plate through an engaging assembly, and the engaging assembly is configured to limit relative movement of the lower case and the heat conducting plate in a height direction and a width direction of the battery module; wherein the engaging assembly comprises a boss formed on the lower case and an engaging hole formed in the heat conducting plate, and the boss is engaged with and fitted in the engaging hole; wherein the boss comprises a connecting portion and an engaging portion that are connected to each other, and a width of the engaging portion is greater than a width of the connecting portion in the width direction of the battery module; wherein the engaging hole comprises a first hole and a second hole that communicate with each other, and a size of the first hole in the width direction of the battery module is larger than a size of the second hole in the width direction of the battery module; wherein the engaging portion is configured to pass through the first hole, the connecting portion is fitted in the second hole, and the engaging portion is configured to limit the heat conducting plate in the height direction of the battery module; and wherein the boss and the engaging hole form a slidable connection, in such a manner that during assembling, the engaging portion first passes through the first hole and then the heat conducting plate is moved in such a manner that the engaging portion and the connecting portion slide towards the second hole along the first hole, until the connecting portion is engaged in the second hole. a lower case; a plurality of battery cells sequentially stacked and received in the lower case; and a heat conducting plate, wherein the lower case is connected to the heat conducting plate through an engaging assembly, and the engaging assembly is configured to limit relative movement of the lower case and the heat conducting plate in a height direction and a width direction of the battery module; wherein the engaging assembly comprises a boss formed on the lower case and an engaging hole formed in the heat conducting plate, and the boss is engaged with and fitted in the engaging hole; wherein the boss comprises a connecting portion and an engaging portion that are connected to each other, and a width of the engaging portion is greater than a width of the connecting portion in the width direction of the battery module; wherein the engaging hole comprises a first hole and a second hole that communicate with each other, and a size of the first hole in the width direction of the battery module is larger than a size of the second hole in the width direction of the battery module; wherein the engaging portion is configured to pass through the first hole, the connecting portion is fitted in the second hole, and the engaging portion is configured to limit the heat conducting plate in the height direction of the battery module; and wherein the boss and the engaging hole form a slidable connection, in such a manner that during assembling, the engaging portion first passes through the first hole and then the heat conducting plate is moved in such a manner that the engaging portion and the connecting portion slide towards the second hole along the first hole, until the connecting portion is engaged in the second hole.