A battery frame, comprising at least two frames, wherein each frame comprises a pallet and side plates, the side plates are peripherally connected to the pallet and comprise a first side plate and a second side plate that are arranged oppositely along a first direction, the first direction is parallel to a plane in which the pallet is located, and the at least two frames are sequentially connected along the first direction; in the at least two frames, any two adjacent frames are rotatably connected to each other, so that the battery frame is in either an unfolded state or a folded state; when the battery frame is in the unfolded state, the at least two frames are disposed alongside in the first direction; when the battery frame is in the folded state, the at least two frames are stacked along a second direction; and the second direction is perpendicular to the plane in which the pallet is located; wherein the battery frame comprises at least three frames; and, among any three adjacent frames, a middle frame is folded in an opposite direction against two frames located on two sides; wherein among any three adjacent frames, the middle frame is rotatably connected to a frame on a first side of the middle frame through a first rotation structure, the middle frame is rotatably connected to a frame on a second side of the middle frame through a second rotation structure, and the first rotation structure and the second rotation structure are located at two ends of the frame along the second direction, so that the middle frame is folded in an opposite direction against the two frames located on two sides; wherein a hollow-out portion is further disposed on the frame, and the hollow-out portion is configured to fit an electrical connecting plate of a battery group; wherein the electrical connecting plate comprises a first bend portion and a second bend portion that are connected to each other, and the first bend portion and the second bend portion are at an angle to each other and are located in two adjacent frames respectively; and, wherein the hollow-out portion comprises a first hollow-out portion and a second hollow-out portion, the first hollow-out portion is located on a side plate and penetrates the side plate along a thickness direction of the side plate, and the second hollow-out portion is located on the pallet and penetrates the pallet along a thickness direction of the pallet. wherein the battery frame comprises at least three frames; and, among any three adjacent frames, a middle frame is folded in an opposite direction against two frames located on two sides; wherein among any three adjacent frames, the middle frame is rotatably connected to a frame on a first side of the middle frame through a first rotation structure, the middle frame is rotatably connected to a frame on a second side of the middle frame through a second rotation structure, and the first rotation structure and the second rotation structure are located at two ends of the frame along the second direction, so that the middle frame is folded in an opposite direction against the two frames located on two sides; wherein a hollow-out portion is further disposed on the frame, and the hollow-out portion is configured to fit an electrical connecting plate of a battery group; wherein the electrical connecting plate comprises a first bend portion and a second bend portion that are connected to each other, and the first bend portion and the second bend portion are at an angle to each other and are located in two adjacent frames respectively; and, wherein the hollow-out portion comprises a first hollow-out portion and a second hollow-out portion, the first hollow-out portion is located on a side plate and penetrates the side plate along a thickness direction of the side plate, and the second hollow-out portion is located on the pallet and penetrates the pallet along a thickness direction of the pallet.