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 (Z) and a width direction (X) 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 (X) 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 (X) of the battery module is larger than a size of the second hole in the width direction (X) 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 (Z) 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 (Z) and a width direction (X) 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 (X) 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 (X) of the battery module is larger than a size of the second hole in the width direction (X) 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 (Z) 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 . <EOS>