A battery module, comprising: a harness isolation board provided with a mounting groove; an output pole connection sheet provided with a through hole; and a fixing assembly provided on the harness isolation board; wherein the fixing assembly comprises: a connecting member placed in the mounting groove and engaged with the mounting groove to be fixed on the harness isolation board; and a fastening member securely connected to the connecting member, cooperating with the through hole, and fixing the output pole connection sheet; the mounting groove of the harness isolation board is provided with a first engaging portion; the connecting member is provided with a second engaging portion; the first engaging portion and the second engaging portion are latched with each other to limit a circumferential displacement of the connecting member in the mounting groove that, under the engagement between the first engaging portion and the second engaging portion, the connecting member will not move in the plane where a bottom surface of the mounting groove is present, characterized in that the first engaging portion is a recessed groove, and the second engaging portion is a protrusion latched with the recessed groove; or the first engaging portion is a protrusion, and the second engaging portion is a recessed groove latched with the protrusion, the first engaging portion is provided in one pair or multiple pairs, and the second engaging portion is provided in one pair or multiple pairs. a harness isolation board provided with a mounting groove; an output pole connection sheet provided with a through hole; and a fixing assembly provided on the harness isolation board; wherein the fixing assembly comprises: a connecting member placed in the mounting groove and engaged with the mounting groove to be fixed on the harness isolation board; and a fastening member securely connected to the connecting member, cooperating with the through hole, and fixing the output pole connection sheet; the mounting groove of the harness isolation board is provided with a first engaging portion; the connecting member is provided with a second engaging portion; the first engaging portion and the second engaging portion are latched with each other to limit a circumferential displacement of the connecting member in the mounting groove that, under the engagement between the first engaging portion and the second engaging portion, the connecting member will not move in the plane where a bottom surface of the mounting groove is present, characterized in that the first engaging portion is a recessed groove, and the second engaging portion is a protrusion latched with the recessed groove; or the first engaging portion is a protrusion, and the second engaging portion is a recessed groove latched with the protrusion, the first engaging portion is provided in one pair or multiple pairs, and the second engaging portion is provided in one pair or multiple pairs. a connecting member placed in the mounting groove and engaged with the mounting groove to be fixed on the harness isolation board; and a fastening member securely connected to the connecting member, cooperating with the through hole, and fixing the output pole connection sheet; the mounting groove of the harness isolation board is provided with a first engaging portion; the connecting member is provided with a second engaging portion; the first engaging portion and the second engaging portion are latched with each other to limit a circumferential displacement of the connecting member in the mounting groove that, under the engagement between the first engaging portion and the second engaging portion, the connecting member will not move in the plane where a bottom surface of the mounting groove is present, characterized in that the first engaging portion is a recessed groove, and the second engaging portion is a protrusion latched with the recessed groove; or the first engaging portion is a protrusion, and the second engaging portion is a recessed groove latched with the protrusion, the first engaging portion is provided in one pair or multiple pairs, and the second engaging portion is provided in one pair or multiple pairs.